Fixed softlock forcing you to found a pantheon without available beliefs

[xlenstra]

Savefile to reproduce:
Invalid Pantheon Found.txt

The problem was that when you found a religion, a new Religion object is created, that shares a pantheon Belief with your previous pantheon religion. Thus, just counting the amount of beliefs in each existing Religion over-estimates the amount of Beliefs of type Pantheon actually used in the game. As we only check if the amount of beliefs left of a certain type equals 0, this check would in the save file above return true, as there were -9 Beliefs of type Pantheon left. By using a distinct, we ignore these doubly counted pantheons, and thus get the correct number.