Better warning message in add-user.sh

If (shell or environment) variable JBOSS_HOME is set to something unexpected, then add-user.sh complains:

"WARNING JBOSS_HOME may be pointing to a different installation - unpredictable results may occur."

This can be made clearer, e.g.:

"WARNING: The JBOSS_HOME (/usr/java/jboss7) that this script will use may indicate a different installation than the one this script resides in (/usr/local/java/wildfly) - unpredictable results may occur."

Change of line 35 in "bin/add-user.sh":

echo "WARNING: The JBOSS_HOME ($SANITIZED_JBOSS_HOME) that this script will use may indicate a different installation than the one this script resides in ($RESOLVED_JBOSS_HOME) - unpredictable results may occur."