Send 50% less debug information when executing cmd
Send 50% less debug information when executing cmd

The current code prints out the command it runs twice: once in
'create_process' or 'execute_rootwrap_daemon', and once after the
command has finished executing and a return code is returned. Since this
is synchronous, there is no need to print the command twice in a row, so
this patch deletes the latter one, leaving only the exit code to be
printed.

This patch also refactors the surrounding code to make it more readable.

Change-Id: I22289f838dbc3956a777a78c882e4d5f1e725d0e

noironetworks/neutron,igor-toga/local-snat,wolverineav/neutron,MaximNevrov/neutron,sebrandon1/neutron,chitr/neutron,eayunstack/neutron,huntxu/neutron,huntxu/neutron,mahak/neutron,apporc/neutron,cloudbase/neutron,apporc/neutron,openstack/neutron,eayunstack/neutron,openstack/neutron,mahak/neutron,klmitch/neutron,bigswitch/neutron,noironetworks/neutron,igor-toga/local-snat,mahak/neutron,dims/neutron,chitr/neutron,klmitch/neutron,wolverineav/neutron,cloudbase/neutron,sebrandon1/neutron,bigswitch/neutron,MaximNevrov/neutron,dims/neutron,openstack/neutron