Fix broken fstab entry

Whitespace between the fstab option is not valid, remove it.

Change-Id: I1be789acc7bf92811f8d4e2c0f0661ebf3be1678
Closes-Bug: #1762105

lib/swift_storage_utils.py

@@ -477,7 +477,7 @@ def setup_storage():
 
         if loopback_device:
             dev = loopback_device
-            options = "loop, defaults"
+            options = "loop,defaults"
 
         mountpoint = '/srv/node/%s' % basename
         filesystem = "xfs"

unit_tests/test_swift_storage_utils.py

@@ -434,7 +434,7 @@ class SwiftStorageUtilsTests(CharmTestCase):
             '/srv/test.img',
             '/srv/node/test.img',
             'xfs',
-            options='loop, defaults'
+            options='loop,defaults'
         )
 
         self.mkdir.assert_has_calls([