Revert "Let git merge conflict count reflect the number of conflicts, not just the number of conflicting files"

The git merge gives no guarantees about the exit code (contrary to git merge-file)

This reverts commit 98e77491.

Let git merge conflict count reflect the number of conflicts, not just the number of conflicting files

This reverts commit ef56db95

This reverts commit 44992289, reversing
changes made to 9e3e2f64.