R1:24ebac8ad734

Remove unused shouldUse* functions from PhabricatorRepository

Summary:
Calls to private functions `PhabricatorRepository::shouldUseSSH()` and `PhabricatorRepository::shouldUseHTTP()` were removed in https://we.phorge.it/rP29d1115037b84454c4fd186c47f33f162cc337b9.
Call to private function `PhabricatorRepository::shouldUseSVNProtocol()` was removed in https://we.phorge.it/rP575c01373ee77c12b06696b34cfdf43a2eb26c42.

Test Plan: Grep the code; run static code analysis.

Reviewers: O1 Blessed Committers…