ima/policy: fix parsing of fsuuid

ima/policy: fix parsing of fsuuid

BugLink: http://bugs.launchpad.net/bugs/1755804
The switch to uuid_t invereted the logic of verfication that &entry->fsuuid
is zero during parsing of "fsuuid=" rule. Instead of making sure the
&entry->fsuuid field is not attempted to be overwritten, we bail out for
perfectly correct rule.

Fixes: 787d8c530af7 ("ima/policy: switch to use uuid_t")
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
(cherry picked from commit 36447456e1cca853188505f2a964dbbeacfc7a7a)
Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Khaled Elmously <khalid.elmously@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>