Update validation to check for invalid translation files (linuxmint#542)

Author: rcalixte

validate-spice

@@ -47,6 +47,11 @@ def validate_xlet(uuid):
         if len(glob.glob("files/*/po/*.pot")) > 1:
             raise CheckError(f"[{uuid}] Too many .pot files!")
 
+        # Check if there are any improperly named file(s)
+        for file in glob.glob("files/*/po/*"):
+            if not (file.endswith(".po") or file.endswith(".pot")):
+                raise CheckError(f"[{uuid}] Invalid file found in translation directory: {file}")
+
         # Check forbidden .nemo_action.in format
         keyfile = GLib.KeyFile.new()
         try: