Wrong sentences counting in intents list

[johncordeiro]

Description:
In the intents list, it shows the number of sentences related to it, but when you remove sentences they still are considered for the counting.

Browser: Chrome
OS: OSX
Authenticated: Yes
URL: https://staging.bothub.it

Steps to reproduce the error:

1. Add a sentence with the Intent "positive";
2. In the "Trainings" tab you see the list of Intents with 1 sentence inside;

3. You remove the sentence related to it;
4. You add a new sentence to the same intent "positive" and now you see 2 sentences instead of just one;

5. When you click in the Intent you see just one.