LU-9231 tests: cleanup obdecho before iokit exit

LU-9231 tests: cleanup obdecho before iokit exit

Otherwise under some failure cases, it may leave the
FID_SEQ_LOCAL_NAME local object which is used by the
obdecho in the system, then the subsequent tests can
NOT exit cleanly.

Lustre-commit: c5675497b411d8b3f0f08fec3271fd528b4a52cf
Lustre-change: http://review.whamcloud.com/23738

Test-Parameters: alwaysuploadlogs envdefinitions=PTLDEBUG=-1,DEBUG_SIZE=150 mdtfilesystemtype=ldiskfs ostfilesystemtype=ldiskfs clientdistro=el7 ossdistro=el7 mdsdistro=el7 mdscount=2 mdtcount=4 testlist=mds-survey,mmp,mds-survey,mmp,mds-survey,mmp
Signed-off-by: Fan Yong <fan.yong@intel.com>
Signed-off-by: Bob Glossman <bob.glossman@intel.com>
Change-Id: I741cf20875df679ecdf72d5461cc14eec166e3ae
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-on: https://review.whamcloud.com/26092
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>