enlightenment_remote: restore compatibility with older versions with bg-add / bg-del
enlightenment_remote: restore compatibility with older versions with bg-add / bg-del

Summary:
older versions of enlightenment_remote had a additional first param that did nothing
this change detects if that paramater is still passed in and ignores it. There are
a couple of applications including variety that rely on this behavior as well as some
user scripts

Reviewers: zmike, raster

Subscribers: cedric

Differential Revision: https://phab.enlightenment.org/D2813

FlorentRevest/Enlightenment,tizenorg/platform.upstream.enlightenment,tasn/enlightenment,FlorentRevest/Enlightenment,tasn/enlightenment,tizenorg/platform.upstream.enlightenment,rvandegrift/e,rvandegrift/e,tasn/enlightenment,tizenorg/platform.upstream.enlightenment,FlorentRevest/Enlightenment,rvandegrift/e