locale.c: locale "" can be disparate

Setting a locale "" means to get the value from environment variables.
These can set locale categories to different locales, and this needs to
be handled.  The logic before this commit only handled the disparate
case when the locale wasn't ""; but this was compensated for elsewhere.
A future commit will remove that compensation.

locale.c

@@ -992,7 +992,8 @@ S_emulate_setlocale_i(pTHX_
             }
         }
     }   /* End of this being setlocale(LC_foo, "") */
-    else if (strchr(new_locale, ';')) {
+
+    if (strchr(new_locale, ';')) {
         return setlocale_from_aggregate_LC_ALL(new_locale);
     }