LU-1538 tests: standardize test script init – full group

LU-1538 tests: standardize test script init – full group

Standardize the initial Lustre test script initialization for
clarity and consistency for test suites in the full test group.

The LUSTRE path is already normalized in init_test_env(), so this
doesn't need to be done in the caller.  Use $(...) subshells instead
of `...` in the affected lines.  Remove NAME, SRCDIR, PATH, MULTIOP,
SETUP, CLEANUP, CHECKSTAT, TMP, SAVE_PWD, variable initialization,
since it is already done in init_test_env() or not needed in the test
scripts.

Move all definitions of ALWAYS_EXCEPT and SLOW to after
init_test_env() and init_logging() and call build_test_filter()
immediately after the ALWAYS_EXCEPT and SLOW definitions.

Test-Parameters: trivial
Test-Parameters: envdefinitions=SLOW=yes,ENABLE_QUOTA=yes clientcount=2 osscount=1 ostcount=7 mdscount=1 mdtcount=1 austeroptions=-R iscsi=1 testlist=metadata-updates,performance-sanity,racer
Test-Parameters: envdefinitions=SLOW=yes,ENABLE_QUOTA=yes clientcount=2 osscount=1 ostcount=7 mdscount=1 mdtcount=1 austeroptions=-R testlist=obdfilter-survey,sanity-benchmark,sanity-lsnapshot

Signed-off-by: James Nunez <jnunez@whamcloud.com>
Change-Id: I6e21a4a5d9e9215d5b452c4fd30467d9c007b5a5
Reviewed-on: https://review.whamcloud.com/36359
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Emoly Liu <emoly@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>