LU-4808 tests: sanity cleanup to work on Xeon Phi

LU-4808 tests: sanity cleanup to work on Xeon Phi

* Made the test_74c robust to different platforms.
* Fix an issue with values more than 2^32 (for example 9.36473e+09).
* Fix an integer comparison in case of empty variable.
* Check for tools presents (rsync and getfattr).
* Check for CLIENTONLY mode.
* Remove "-x" options from grep (it's not always supported).
* Coding style cleanup.

Signed-off-by: Dmitry Eremin <dmitry.eremin@intel.com>
Change-Id: I53671f9a6ca2efa0a8f3e5634bfe4d6e8d204078
Reviewed-on: http://review.whamcloud.com/9766
Tested-by: Jenkins
Reviewed-by: Jian Yu <jian.yu@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Minh Diep <minh.diep@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>