Merge branch 'tr/receive-pack-aliased-update-fix' into maint

* tr/receive-pack-aliased-update-fix:
check_aliased_update: strcpy() instead of strcat() to copy
receive-pack: detect aliased updates which can occur with symrefs
receive-pack: switch global variable 'commands' to a parameter

Conflicts:
t/t5516-fetch-push.sh