glusterd: log enhancements for volume start

* changed some of the log messages to give as much information as
  available in case of failure

* added logs to identify on which machine lock/stage/commit failed

* added macros to represent error strings to maintain uniformity
  among error messages for a given kind of error

* moved error logs wherever possible, from caller to callee to avoid
  code duplication

Change-Id: I0e98d5d3ba086c99240f2fbd642451f175f51942
BUG: 812356
Signed-off-by: Krutika Dhananjay <kdhananj@redhat.com>
Reviewed-on: http://review.gluster.org/4353
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Tested-by: Vijay Bellur <vbellur@redhat.com>