LU-3587 tests: add sanity test for crash in changelog

LU-3587 tests: add sanity test for crash in changelog

This patch adds a sanity test to verify that the previous fixes committed
for this bug prevent a crash during a changelog fetch after renaming
one very long filename to another.

Test-Parameters: testlist=sanity envdefinitions=ONLY=160b

Lustre-commit: 3f2ad881802092ef359aa3cf2040978829d444c4
Lustre-change: http://review.whamcloud.com/7751

Signed-off-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Change-Id: Ia2c9147dcb88f00c56df3e72bb0738c8142c034f
Reviewed-on: http://review.whamcloud.com/8171
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>