rpcserver: fix exception handling for FAST armor failure

Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>

ipalib/errors.py

@@ -249,7 +249,7 @@ class KrbPrincipalWrongFAST(PrivateError):
     """
     Raised when it is not possible to use our FAST armor for kinit
     """
-    format = '%(principal) cannot use Anonymous PKINIT as a FAST armor'
+    format = '%(principal)s cannot use Anonymous PKINIT as a FAST armor'
 
 ##############################################################################
 # Public errors:

ipaserver/rpcserver.py

@@ -1103,8 +1103,7 @@ class login_password(Backend, KerberosSession):
                                  message=unicode(e))
             elif ('kinit: Error constructing AP-REQ armor: '
                   'Matching credential not found') in str(e):
-                raise KrbPrincipalWrongFAST(principal=principal,
-                                            message=unicode(e))
+                raise KrbPrincipalWrongFAST(principal=principal)
             raise InvalidSessionPassword(principal=principal,
                                          message=unicode(e))