Merge branch 'sp/shallow-deepen-relative-fix'

"git fetch --deepen" that tries to go beyond merged branch used to
get confused where the updated shallow points are, which has been
corrected.

* sp/shallow-deepen-relative-fix:
  shallow: handling fetch relative-deepen
  shallow: free local object_array allocations

diff --cc shallow.c
Simple merge

diff --cc shallow.h
Simple merge

diff --cc t/t5500-fetch-pack.sh
Simple merge