remove unneeded p2.inf instructions re: jbds feature refactoring (from 8.0.0)

p2.inf files were created to support name change from com.jboss.jbds.product.feature.source to com.jboss.devstudio.core.feature.source and support name change from com.jboss.jbds.product.feature to com.jboss.devstudio.core.feature. Since we're on JBDS 9 and it can't be updated from 8, this instruction is no longer needed.