Merge branch 'nd/resolve-ref'

* nd/resolve-ref:
Rename resolve_ref() to resolve_ref_unsafe()
Convert resolve_ref+xstrdup to new resolve_refdup function
revert: convert resolve_ref() to read_ref_full()

diff --cc branch.c
Simple merge

diff --cc builtin/branch.c
Simple merge

diff --cc builtin/checkout.c
Simple merge

diff --cc builtin/commit.c
Simple merge

diff --cc builtin/merge.c
Simple merge

diff --cc builtin/revert.c
Simple merge

diff --cc cache.h
Simple merge