Merge branch 'ua/call-repo-config-with-possibly-null-repository'

Since a call to repo_config() can be called with repo set to NULL
these days, a command that is marked as RUN_SETUP in the builtin
command table does not have to check repo with NULL before making
the call.

* ua/call-repo-config-with-possibly-null-repository:
  builtin/difftool: remove unnecessary if statement
  builtin/add: remove unnecessary if statement

diff --cc builtin/difftool.c
Simple merge