cluster/afr: fix fd leak with unsafe call_resume()

Introduce AFR_CALL_RESUME macro which cleans up frame->local, like
how AFR_STACK_UNWIND etc. do.

Therefore fix leak in afr_fsync() path.

Change-Id: I3855d8e7e84dbc44e05f507563b7f722bf9621b8
BUG: 927146
Signed-off-by: Anand Avati <avati@redhat.com>
Reviewed-on: http://review.gluster.org/4745
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>