Gitea no longer works on git 1.7.2

[zeripath]

• Gitea version (or commit ref): master
• Git version: 1.7.2
• Operating system:
• Database (use [x]):
  • PostgreSQL
  • MySQL
  • MSSQL
  • SQLite
  • Not relevant
• Can you reproduce the bug at https://try.gitea.io:
  • Yes (provide example URL)
  • No
  • Not relevant
• Log gist:

Description

There are multiple problems whereby options have been added to git commands which are unavailable in early git versions.

• git remote remove. This is not available in git < 1.8.0 - rm is an alias for it.
• git config --local. This is not available in git < 1.8.0 - config is an appropriate alias.
• git commit-tree -m. This is not available in git < 1.8.0 - the message can simply be passed in as a stdin.
• git check-attr --cached. This is not available in git < 1.8.0. It will use the cached version in any case in 1.7 and this option is not used.
• git fetch and git pull do not behave the same way in git < 2.0.0 to the way expected in merge.go.