LU-10857 tests: allow to disable project quotas

LU-10857 tests: allow to disable project quotas

Project quotas is disabled by default, sanity-quota.sh
enables it always if project quota supported.
Patch adds the possibility to disable project quotas
for regular user/group quota testing by using
ENABLE_PROJECT_QUOTAS=false.

Test-Parameters: trivial testlist=sanity-quota envdefinitions=ENABLE_PROJECT_QUOTAS=false
Signed-off-by: Elena Gryaznova <c17455@cray.com>
Change-Id: I48176898fd940d66d0ebee4ef085a0bcece02ee9
Reviewed-on: https://review.whamcloud.com/31796
Tested-by: Jenkins
Reviewed-by: Wang Shilong <wshilong@ddn.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andrew Perepechko <c17827@cray.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>