libafs: check afs_InitReq return code

libafs: check afs_InitReq return code

Do not ignore the return code from afs_InitReq everywhere it is
called. If afs_InitReq fails, the vrequest could not be initialized
for some reason.

Change-Id: Ibae9f93c1e20a9fcae812f047da14106e6717454
Reviewed-on: http://gerrit.openafs.org/11097
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Reviewed-by: D Brashear <shadow@your-file-system.com>