[gnome-online-accounts/gnome-3-18] identity: Don't ever nullify identifier

[Debarshi Ray <debarshir src gnome org>]

commit f4186d2e3992cfc60bc36ec2282eebe868a5a7b9
Author: Ray Strode <rstrode redhat com>
Date:   Tue Sep 22 14:41:05 2015 -0400

    identity: Don't ever nullify identifier
    
    Credentials stored in the kernel keyring disappear after they expire.
    This is different from other credential caches, which hang around but
    maintain an expired timestamp until kdestroy. Because the credentials
    vanish, trying to read the principal from an previously existing
    credential cache will yield NULL.
    
    This can lead to a crash because we never expect the identifier of an
    identity object to be NULL. So make sure we retain the old identifier
    in the event the credential cache gets wiped.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=756494

 src/goaidentity/goakerberosidentity.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/goaidentity/goakerberosidentity.c b/src/goaidentity/goakerberosidentity.c
index 4370a09..1ce5079 100644
--- a/src/goaidentity/goakerberosidentity.c
+++ b/src/goaidentity/goakerberosidentity.c
@@ -1345,7 +1345,7 @@ update_identifier (GoaKerberosIdentity *self, GoaKerberosIdentity *new_identity)
   char *new_identifier;
 
   new_identifier = get_identifier (self, NULL);
-  if (g_strcmp0 (self->priv->identifier, new_identifier) != 0)
+  if (g_strcmp0 (self->priv->identifier, new_identifier) != 0 && new_identifier != NULL)
     {
       g_free (self->priv->identifier);
       self->priv->identifier = new_identifier;