make this a comment a coverity queller

Change-Id: I0eccec058f506be69f6c95a1a6d97be64cb734bc

sal/rtl/ustring.cxx

@@ -569,10 +569,10 @@ void SAL_CALL rtl_uString_newFromCodePoints(
             ++n;
         }
     }
-    /* Builds on the assumption that sal_Int32 uses 32 bit two's complement
-       representation with wrap around (the necessary number of UTF-16 code
-       units will be no larger than 2 * SAL_MAX_INT32, represented as
-       sal_Int32 -2): */
+    /* coverity[dead_error_condition] - Builds on the assumption that sal_Int32
+       uses 32 bit two's complement representation with wrap around (the
+       necessary number of UTF-16 code units will be no larger than 2 *
+       SAL_MAX_INT32, represented as sal_Int32 -2): */
     if (n < 0) {
         *newString = NULL;
         return;