Fix cred leak in zpl_fallocate_common
This is caught by kmemleak when running compress_004_pos
Reviewed-by: Tim Chase <tim@chase2k.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes #5244
Closes #5330