Incorrect regex parsing in start script of kafka image

In Docker-entrypoint script of kafka image, there is a regex that incorrectly parses global variables containing character '='.

The regex

for VAR in `env`
do
env_var=`echo "$VAR" | sed -r "s/(.)=./\1/g"`
...
done

Incorrectly parsed variable

export KAFKA_LOG4J_OPTS="-Dlog4j.configuration=file:$KAFKA_HOME/config/log4j.properties"
Expected content of $env_var is "KAFKA_LOG4J_OPTS."
Actual content of $env_var is "KAFKA_LOG4J_OPTS=-Dlog4j.configuration"