I changed the listeners for undertow in standalone-full.xml this way:
400,402c363
< <http-listener name="http" socket-binding="http"/>
< <https-listener name="https" socket-binding="https" security-realm="UndertowRealm" />
< <ajp-listener name="ajp" socket-binding="ajp"/>
—
> <http-listener name="default" socket-binding="http"/>

When accessing my web app through apache httpd using the ajp connector I see this error:
12:47:21,145 ERROR io.undertow.request#handleFirstRequest Servlet request failed io.undertow.server.HttpServerExchange@9bae4f: java.lang.StringIndexOutOfBoundsException: String index out of range: -1
at java.lang.String.substring(String.java:1911) [rt.jar:1.7.0_21]
at io.undertow.security.handlers.SinglePortConfidentialityHandler.getRedirectURI(SinglePortConfidentialityHandler.java:55) [undertow-core-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.getRedirectURI(ServletConfidentialityConstraintHandler.java:55) [undertow-servlet-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:49) [undertow-core-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.server.HttpHandlers.executeHandler(HttpHandlers.java:46) [undertow-core-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.servlet.handlers.security.ServletSecurityConstraintHandler.handleRequest(ServletSecurityConstraintHandler.java:56) [undertow-servlet-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.server.HttpHandlers.executeHandler(HttpHandlers.java:46) [undertow-core-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:58) [undertow-core-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.server.HttpHandlers.executeHandler(HttpHandlers.java:46) [undertow-core-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:66) [undertow-servlet-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.server.HttpHandlers.executeHandler(HttpHandlers.java:46) [undertow-core-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.security.handlers.SecurityInitialHandler.handleRequest(SecurityInitialHandler.java:71) [undertow-core-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.server.HttpHandlers.executeHandler(HttpHandlers.java:46) [undertow-core-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:26) [undertow-core-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at org.wildfly.extension.undertow.security.SecurityContextCreationHandler.handleRequest(SecurityContextCreationHandler.java:56)
at io.undertow.server.HttpHandlers.executeHandler(HttpHandlers.java:46) [undertow-core-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:26) [undertow-core-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:118) [undertow-servlet-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:106) [undertow-servlet-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.servlet.handlers.ServletInitialHandler.handleRequest(ServletInitialHandler.java:83) [undertow-servlet-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.server.HttpHandlers.executeRootHandler(HttpHandlers.java:52) [undertow-core-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.servlet.handlers.DefaultServlet$1.run(DefaultServlet.java:216) [undertow-servlet-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.util.SameThreadExecutor.execute(SameThreadExecutor.java:17) [undertow-core-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.server.HttpHandlers.executeRootHandler(HttpHandlers.java:60) [undertow-core-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:544) [undertow-core-1.0.0.Alpha15.jar:1.0.0.Alpha15]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [rt.jar:1.7.0_21]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [rt.jar:1.7.0_21]
at java.lang.Thread.run(Thread.java:722) [rt.jar:1.7.0_21]