Check for duplicate winsync agreement before trying to set one up.

We currently only support a single winsync agreement so all we need
to do is check to see if we have one with the remote host.

This also adds some minor exception handling cleanup.

https://fedorahosted.org/freeipa/ticket/2130

install/tools/ipa-replica-manage

@@ -199,10 +199,7 @@ def del_link(realm, replica1, replica2, dirman_passwd, force=False):
             print "Please use the 'del' command to remove it from the domain"
             return
 
-    except ldap.NO_SUCH_OBJECT:
-        print "'%s' has no replication agreement for '%s'" % (replica1, replica2)
-        return
-    except errors.NotFound:
+    except (ldap.NO_SUCH_OBJECT, errors.NotFound):
         print "'%s' has no replication agreement for '%s'" % (replica1, replica2)
         return
     except Exception, e:
@@ -219,11 +216,7 @@ def del_link(realm, replica1, replica2, dirman_passwd, force=False):
                 print "Please use the 'del' command to remove it from the domain"
                 return
 
-        except ldap.NO_SUCH_OBJECT:
-            print "'%s' has no replication agreement for '%s'" % (replica2, replica1)
-            if not force:
-                return
-        except errors.NotFound:
+        except (ldap.NO_SUCH_OBJECT, errors.NotFound):
             print "'%s' has no replication agreement for '%s'" % (replica2, replica1)
             if not force:
                 return
@@ -357,6 +350,18 @@ def add_link(realm, replica1, replica2, dirman_passwd, options):
             root_logger.error("winsync agreements need to be created as root")
             sys.exit(1)
 
+    # See if we already have an agreement with this host
+    try:
+        repl = replication.ReplicationManager(realm, replica1, dirman_passwd)
+        if repl.get_agreement_type(replica2) == replication.WINSYNC:
+            agreement = repl.get_replication_agreement(replica2)
+            sys.exit("winsync agreement already exists on subtree %s" % 
+                agreement.getValue('nsds7WindowsReplicaSubtree'))
+        else:
+            sys.exit("A replication agreement to %s already exists" % replica2)
+    except errors.NotFound:
+        pass
+
     if options.cacert:
         # have to install the given CA cert before doing anything else
         ds = dsinstance.DsInstance(realm_name = realm,
@@ -372,10 +377,7 @@ def add_link(realm, replica1, replica2, dirman_passwd, options):
     try:
         repl1 = replication.ReplicationManager(realm, replica1, dirman_passwd)
 
-    except ldap.NO_SUCH_OBJECT:
-        print "Cannot find replica '%s'" % replica1
-        return
-    except errors.NotFound:
+    except (ldap.NO_SUCH_OBJECT, errors.NotFound):
         print "Cannot find replica '%s'" % replica1
         return
     except Exception, e: