LU-1538 tests: standardize test script init - lnet

LU-1538 tests: standardize test script init - lnet

Standardize the initial Lustre test script initialization for clarity
and consistency.

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, PATH, SAVE_PWD,
RLUSTRE, MULTIOP variable initialization, since it is already done in
init_test_env() or not needed in the test script.

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: testgroup=review-dne-zfs-part-3
Signed-off-by: James Nunez <jnunez@whamcloud.com>
Change-Id: I491cf3e282a1f31fb8c87440554445d708c6da1e
Reviewed-on: https://review.whamcloud.com/35254
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Wei Liu <sarah@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>