Merge branch 'maint'

Merge branch 'maint'

* maint:
  Update release notes for 1.6.0.3
  Teach rebase -i to honor pre-rebase hook
  docs: describe pre-rebase hook
  do not segfault if make_cache_entry failed
  make prefix_path() never return NULL
  fix bogus "diff --git" header from "diff --no-index"
  Fix fetch/clone --quiet when stdout is connected
  builtin-blame: Fix blame -C -C with submodules.
  bash: remove fetch, push, pull dashed form leftovers

Conflicts:
	diff.c