Description of problem:

When in the 'Add account' dialog of the user panel, if click 'Add' and then cancel, I get an abort.

Version-Release number of selected component (if applicable):

Name        : control-center
Arch        : x86_64
Epoch       : 1
Version     : 3.8.1
Release     : 2.fc19

How reproducible:

Every time

Steps to Reproduce:
1. User panel
2. Unlock
3. [+]
4. Enterprise login
5. Domain: blah.com, User: auou, Password: onuto
6: Add
7: Cancel (while spinner)
  
Actual results:

(gnome-control-center:6040): user-accounts-cc-panel-CRITICAL **: um_realm_manager_discover_finish: assertion `UM_IS_REALM_MANAGER (self)' failed
**
user-accounts-cc-panel:ERROR:um-account-dialog.c:724:on_realm_discover_input: assertion failed: (realms != NULL)

(gdb) bt
#0  0x0000003f9a835819 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#1  0x0000003f9a836f28 in __GI_abort () at abort.c:90
#2  0x0000003f9cc6bd16 in g_assertion_message (domain=domain@entry=0x53cdc4 "user-accounts-cc-panel", file=file@entry=0x53d9ff "um-account-dialog.c", line=line@entry=724, 
    func=func@entry=0x53dcc0 <__PRETTY_FUNCTION__.48758> "on_realm_discover_input", message=<optimized out>) at gtestutils.c:1912
#3  0x0000003f9cc6bd74 in g_assertion_message_expr (domain=domain@entry=0x53cdc4 "user-accounts-cc-panel", file=file@entry=0x53d9ff "um-account-dialog.c", 
    line=line@entry=724, func=func@entry=0x53dcc0 <__PRETTY_FUNCTION__.48758> "on_realm_discover_input", expr=expr@entry=0x53dbcc "realms != NULL") at gtestutils.c:1923
#4  0x00000000004bf086 in on_realm_discover_input (source=<optimized out>, result=<optimized out>, user_data=<optimized out>) at um-account-dialog.c:724
#5  0x0000003f9e46b4e7 in g_simple_async_result_complete (simple=0x1af3990 [GSimpleAsyncResult]) at gsimpleasyncresult.c:777
#6  0x00000000004cb2a2 in on_provider_discover (source=<optimized out>, result=<optimized out>, user_data=<optimized out>) at um-realm-manager.c:357
#7  0x0000003f9e46b4e7 in g_simple_async_result_complete (simple=0xd23070 [GSimpleAsyncResult]) at gsimpleasyncresult.c:777
#8  0x0000003f9e4c3b8d in reply_cb (connection=<optimized out>, res=<optimized out>, user_data=0xd23070) at gdbusproxy.c:2632
#9  0x0000003f9e46b4e7 in g_simple_async_result_complete (simple=0xd230e0 [GSimpleAsyncResult]) at gsimpleasyncresult.c:777
#10 0x0000003f9e4b92c6 in g_dbus_connection_call_done (source=<optimized out>, result=<optimized out>, user_data=0x1b302c0) at gdbusconnection.c:5333
#11 0x0000003f9e46b4e7 in g_simple_async_result_complete (simple=0x1404aa0 [GSimpleAsyncResult]) at gsimpleasyncresult.c:777
#12 0x0000003f9e46b549 in complete_in_idle_cb (data=<optimized out>) at gsimpleasyncresult.c:789
#13 0x0000003f9cc47f56 in g_main_dispatch (context=0xbaf9d0) at gmain.c:3054
#14 g_main_context_dispatch (context=context@entry=0xbaf9d0) at gmain.c:3630
#15 0x0000003f9cc482a8 in g_main_context_iterate (context=context@entry=0xbaf9d0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at gmain.c:3701
#16 0x0000003f9cc4834c in g_main_context_iteration (context=0xbaf9d0, context@entry=0x0, may_block=may_block@entry=1) at gmain.c:3762
#17 0x0000003f9e496564 in g_application_run (application=0xbac010 [CcApplication], argc=argc@entry=1, argv=argv@entry=0x7fffffffdac8) at gapplication.c:1623
#18 0x0000000000449348 in main (argc=1, argv=0x7fffffffdac8) at main.c:52


Expected results:

Cancels dialog.