tests/qemu-iotests: skip 108 when FUSE is not loaded

In certain container environments we may not have FUSE at all, so skip
the test in this circumstance too.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20220616142659.3184115-3-jsnow@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>

tests/qemu-iotests/108

@@ -60,6 +60,11 @@ if sudo -n losetup &>/dev/null; then
 else
     loopdev=false
 
+    # Check for usable FUSE in the host environment:
+    if test ! -c "/dev/fuse"; then
+        _notrun 'No passwordless sudo nor usable /dev/fuse'
+    fi
+
     # QSD --export fuse will either yield "Parameter 'id' is missing"
     # or "Invalid parameter 'fuse'", depending on whether there is
     # FUSE support or not.