[glib] gportalsupport: Fix compilation failure from previous commit

[Philip Withnall <pwithnall src gnome org>]

commit f5993c0e5d7405739f415187c90160040ff119ec
Author: Philip Withnall <withnall endlessm com>
Date:   Mon May 1 19:34:51 2017 +0100

    gportalsupport: Fix compilation failure from previous commit
    
    Igor says: Thith code did not path the compilation check.
    
    Signed-off-by: Philip Withnall <withnall endlessm com>

 gio/gportalsupport.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/gio/gportalsupport.c b/gio/gportalsupport.c
index d6d6f41..12b4ffd 100644
--- a/gio/gportalsupport.c
+++ b/gio/gportalsupport.c
@@ -27,12 +27,14 @@ static gboolean network_available;
 static void
 read_flatpak_info (void)
 {
+  const gchar *path = "/.flatpak-info";
+
   if (flatpak_info_read)
     return;
 
   flatpak_info_read = TRUE;
 
-  if (g_file_test ("/.flatpak-info", G_FILE_TEST_EXISTS))
+  if (g_file_test (path, G_FILE_TEST_EXISTS))
     {
       GKeyFile *keyfile;