Description of problem:
No error dialogue when you try to register via auth proxy without selecting "Use Authentication with http proxy" option ,its just one of those cases where user by mistake unchecks the "Use Authentication with http proxy" option after successfully tests connection and closes the proxy configuration dialog 

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


How reproducible:


Steps to Reproduce:
1. Launch GUI
2. Click on register button , Click on configure proxy button
3. Select "I would like to use http proxy" , Enter the valid authorized proxy server details
4. But do not select "Use Authentication with http proxy" option and close the window
5. Now click on next button

Actual results:
No error dialog but traceback on the terminal

Expected results:
Error dilog saying "Server is not reachable at <server datials>" and no trace back on terminal

Additional info:

traceback on terminal:

rhsm.connection.ProxyException: Proxy connection failed: 407
Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/subscription_manager/gui/registergui.py", line 542, in _on_proceed
    self.apply_current_screen()
  File "/usr/lib/python2.6/site-packages/subscription_manager/gui/registergui.py", line 536, in apply_current_screen
    self.current_screen.apply()
  File "/usr/lib/python2.6/site-packages/subscription_manager/gui/registergui.py", line 1867, in apply
    if not is_valid_server_info(conn):
  File "/usr/lib/python2.6/site-packages/subscription_manager/utils.py", line 142, in is_valid_server_info
    conn.ping()
  File "/usr/lib64/python2.6/site-packages/rhsm/connection.py", line 904, in ping
    return self.conn.request_get("/status/")
  File "/usr/lib64/python2.6/site-packages/rhsm/connection.py", line 708, in request_get
    return self._request("GET", method)
  File "/usr/lib64/python2.6/site-packages/rhsm/connection.py", line 597, in _request
    raise ProxyException(e)
rhsm.connection.ProxyException: Proxy connection failed: 407
/usr/sbin/subscription-manager-gui:212: GtkWarning: Attempting to store changes into `/root/.local/share/recently-used.xbel', but failed: Failed to create file '/root/.local/share/recently-used.xbel.OWQQQY': No such file or directory
  sys.exit(ga_Gtk.main() or 0)
/usr/sbin/subscription-manager-gui:212: GtkWarning: Attempting to set the permissions of `/root/.local/share/recently-used.xbel', but failed: No such file or directory
  sys.exit(ga_Gtk.main() or 0)