Prioritize external filters over the internal ones.

Change-Id: I2407a2ebc01f39655b30f7eb1e65deb912f2e606

filter/source/config/cache/typedetection.cxx

@@ -196,8 +196,9 @@ int getFlatTypeRank(const rtl::OUString& rType)
             return n - i - 1;
     }
 
-    // Not ranked.  Treat them equally.
-    return -1;
+    // Not ranked.  Treat them equally.  Unranked filters have higher priority
+    // than the ranked internal ones since they may be external filters.
+    return n;
 }
 
 /**