Fix the validate-comps git status check

...this is how you do that.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

ci/validate-comps

@@ -15,7 +15,7 @@ main() {
     }
 
     # Fail if any changes were made to the repo
-    if [[ -n "(git status --short)" ]]; then
+    if [[ -n $(git status --short) ]]; then
         echo "git status failed!"
         ((failure+=1))
     fi