Merge branch 'jk/log-decorate-opts-with-implicit-decorate'

When "git log" implicitly enabled the "decoration" processing
without being explicitly asked with "--decorate" option, it failed
to read and honor the settings given by the "--decorate-refs"
option.

* jk/log-decorate-opts-with-implicit-decorate:
  log: load decorations with --simplify-by-decoration
  log: handle --decorate-refs with userformat "%d"