Fix krb5_cc_move() issues

Move init/copy/destroy fallback sequence from fcc_move() to
krb5_cc_move().

Make sure all backends's move() method calls krb5_cc_destroy() on the
source on success (and only on success).

In text_cc make sure that we can find in the destination the cred
stored into the source.

lib/krb5/mcache.c

@@ -519,8 +519,8 @@ mcc_move(krb5_context context, krb5_ccache from, krb5_ccache to)
     HEIMDAL_MUTEX_unlock(&(mfrom->mutex));
     HEIMDAL_MUTEX_unlock(&(mto->mutex));
     HEIMDAL_MUTEX_unlock(&mcc_mutex);
-    mcc_destroy(context, from);
 
+    krb5_cc_destroy(context, from);
     return 0;
 }