Check types to avoid AttributeError

"It won't be inexcept... unexcept... it won't
throw an exception" --Ulincsys

Signed-off-by: Seltyk <whhacker.dcx@gmail.com>

augur/application/db/models/augur_operations.py

@@ -996,7 +996,7 @@ class ClientApplication(Base):
     subscriptions = relationship("Subscription")
 
     def __eq__(self, other):
-        return str(self.id) == str(other.id)
+        return isinstance(other, ClientApplication) and str(self.id) == str(other.id)
 
     @staticmethod
     def get_by_id(session, client_id):