new user related gswauth functional tests

New tests around account and user modifications
Testing password changes and invalid admin rights

porting changes to havana branch

Change-Id: I2e867c2bb3ed10f375cc3f20fa66506e2cdd96e6
Reviewed-on: http://review.gluster.org/6223
Reviewed-by: Luis Pabon <lpabon@redhat.com>
Tested-by: Luis Pabon <lpabon@redhat.com>
Signed-off-by: Thiago da Silva <thiago@redhat.com>
Reviewed-on: http://review.gluster.org/6260