LU-11607 tests: create routine to get Lustre env

LU-11607 tests: create routine to get Lustre env

The Lustre tests in the test suites make repeated calls
to a small number functions that relate to the Lustre
environment. Some examples are the version of the Lustre
server or client and the file system type of the server.

Collect these calls into a routine called get_lustre_env()
in the test-framework.sh library and replace calls in
sanity with the global variables.

Test-Parameters: trivial
Signed-off-by: James Nunez <jnunez@whamcloud.com>
Change-Id: I01dd00dd50cca39c964c5fd8abc3f51ab3c8e6b8
Reviewed-on: https://review.whamcloud.com/33938
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Wei Liu <sarah@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>