Revert "Set git branch.autoSetupMerge to always"

This reverts commit d9f557987d.

Makefile

@@ -301,7 +301,6 @@ else
 	$(git_conf) fetch.pruneTags true
 	$(git_conf) push.default current
 	$(git_conf) pull.ff only
-	$(git_conf) branch.autoSetupMerge always
 ifneq (,$(xz))
 	$(git_conf) tar.txz.command "xz -c"
 endif