ipatests: fix for change_principal context manager

The context manager was leaving API object disconnected when
an exception was raised inside of it. This led to resource leak
in the tests.

https://fedorahosted.org/freeipa/ticket/5733

Reviewed-By: Martin Babinsky <mbabinsk@redhat.com>

ipatests/util.py

@@ -696,6 +696,7 @@ def change_principal(user, password, client=None, path=None):
 
     client.Backend.rpcclient.disconnect()
 
+    try:
         with private_ccache(ccache_name):
             kinit_password(user, password, ccache_name)
             client.Backend.rpcclient.connect()
@@ -704,7 +705,7 @@ def change_principal(user, password, client=None, path=None):
                 yield
             finally:
                 client.Backend.rpcclient.disconnect()
-
+    finally:
         client.Backend.rpcclient.connect()
 
 def get_group_dn(cn):