Revert "default run as root user because `erlexec` needs HOME env to be set"

This reverts commit ce91c65a77.

Already set user to run rabbitmq cmds in rabbitmq module to whom
salt-minion running as.
This allow to specify arbitrary user to run those cmds
but still has a saner default than 'root'.
Setting it as 'root' may not work when salt-minion does not run as 'root'.

salt/states/rabbitmq_cluster.py

@@ -29,7 +29,7 @@ def __virtual__():
     return salt.utils.which('rabbitmqctl') is not None
 
 
-def join(name, host, user='rabbit', runas='root'):
+def join(name, host, user='rabbit', runas=None):
     '''
     Ensure the RabbitMQ plugin is enabled.
 

salt/states/rabbitmq_plugin.py

@@ -29,7 +29,7 @@ def __virtual__():
     return False
 
 
-def enabled(name, runas='root'):
+def enabled(name, runas=None):
     '''
     Ensure the RabbitMQ plugin is enabled.
 
@@ -62,7 +62,7 @@ def enabled(name, runas='root'):
     return ret
 
 
-def disabled(name, runas='root'):
+def disabled(name, runas=None):
     '''
     Ensure the RabbitMQ plugin is enabled.
 

salt/states/rabbitmq_policy.py

@@ -37,7 +37,7 @@ def present(name,
             definition,
             priority=0,
             vhost='/',
-            runas='root'):
+            runas=None):
     '''
     Ensure the RabbitMQ policy exists.
 
@@ -108,7 +108,7 @@ def present(name,
 
 def absent(name,
            vhost='/',
-           runas='root'):
+           runas=None):
     '''
     Ensure the named policy is absent
 

salt/states/rabbitmq_user.py

@@ -41,7 +41,7 @@ def present(name,
             force=False,
             tags=None,
             perms=(),
-            runas='root'):
+            runas=None):
     '''
     Ensure the RabbitMQ user exists.
 
@@ -140,7 +140,7 @@ def present(name,
 
 
 def absent(name,
-           runas='root'):
+           runas=None):
     '''
     Ensure the named user is absent
 

salt/states/rabbitmq_vhost.py

@@ -33,11 +33,11 @@ def __virtual__():
 
 def present(name,
             user=None,
-            owner='root',
+            owner=None,
             conf=None,
             write=None,
             read=None,
-            runas='root'):
+            runas=None):
     '''
     Ensure the RabbitMQ VHost exists.
 
@@ -146,7 +146,7 @@ def present(name,
 
 
 def absent(name,
-           runas='root'):
+           runas=None):
     '''
     Ensure the RabbitMQ Virtual Host is absent