Added test_create_access_rule_cephx_admin_user testcase

This test case validates the fix to CVE-2020-27781.

The test will create a share and allow access to "admin" user.
This step should return success, but the access rule for
"admin" will be set to "error".

Related-Bug: #1904015
Depends-On: I1edd5a50079f325fa143a7e0d51b3aa3bb5ed45d
Change-Id: I01157147e749ae6068e9878bffe322cb3993fb60
1 file changed