Fix odb_mkstemp() on AIX

The AIX mkstemp() modifies its template parameter to an empty string if
the call fails.  The existing code had already recomputed the template,
but too late to be good.

See also 6ff6af6, which fixed this problem in a different spot.

Signed-off-by: Mike Ralphson <[email protected]>
Signed-off-by: Johannes Sixt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

wrapper.c

@@ -208,9 +208,10 @@ int odb_mkstemp(char *template, size_t limit, const char *pattern)
 		return fd;
 
 	/* slow path */
-	safe_create_leading_directories(template);
+	/* some mkstemp implementations erase template on failure */
 	snprintf(template, limit, "%s/%s",
 		 get_object_directory(), pattern);
+	safe_create_leading_directories(template);
 	return xmkstemp(template);
 }