convert error number to string

BASIC error type was printing as "Error "+ odd char
 instead of "Error " + error number

Change-Id: I7407833626d6117f932cc29c6dab1a8a64c50b5a
Reviewed-on: https://gerrit.libreoffice.org/14776Reviewed-by: Tor Lillqvist <tml@collabora.com>
Tested-by: Tor Lillqvist <tml@collabora.com>

basic/source/sbx/sbxstr.cxx

@@ -102,7 +102,7 @@ OUString ImpGetString( const SbxValues* p )
         case SbxERROR:
             // Here the String "Error n" is generated
             aRes = SbxRes( STRING_ERRORMSG );
-            aRes += OUString( p->nUShort ); break;
+            aRes += OUString::number(p->nUShort); break;
         case SbxDATE:
             ImpPutDate( &aTmp, p->nDouble ); break;