mem_acct : Check return value of xlator_mem_acct_init().

some code does not check xlator_mem_acct_init() 
return, thus fails to capture wrong memory accounting
initialization. This patch fix the same.

Change-Id: I01eab19d6cef472afd850b0f964132c01523492a
BUG: 1123768
Signed-off-by: Humble Chirammal <hchiramm@redhat.com>
Reviewed-on: http://review.gluster.org/7728
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>
Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>