virfile: virDirCreate: Fix ALLOW_EXIST conditional

I screwed this up in the previous (post 1.2.16) commits

src/util/virfile.c

@@ -2289,7 +2289,7 @@ virDirCreateNoFork(const char *path,
     int ret = 0;
     struct stat st;
 
-    if (!((flags & VIR_DIR_CREATE_ALLOW_EXIST) && !virFileExists(path))) {
+    if (!((flags & VIR_DIR_CREATE_ALLOW_EXIST) && virFileExists(path))) {
         if (mkdir(path, mode) < 0) {
             ret = -errno;
             virReportSystemError(errno, _("failed to create directory '%s'"),