afs: fix memory leak

afs: fix memory leak

An error code is returned by afs_ProcessOpCreate if
this function can not allocate memory for ttargetName.

This function should release the memory previously
allocated for tname and decrement the reference count
of tdp as well.

Reviewed-on: https://gerrit.openafs.org/12208
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
(cherry picked from commit bc123573539084ffc5a16ef1efaaaced5b2be202)

Change-Id: Ia5a09fe860b7a110ad55c111551702e20367ba1b
Reviewed-on: https://gerrit.openafs.org/12309
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Marcio Brito Barbosa <mbarbosa@sinenomine.net>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>