Merge branch 'jk/war-on-git-path'

While handy, "git_path()" is a dangerous function to use as a
callsite that uses it safely one day can be broken by changes
to other code that calls it.  Reduction of its use continues.

* jk/war-on-git-path:
  am: drop "dir" parameter from am_state_init
  replace strbuf_addstr(git_path()) with git_path_buf()
  replace xstrdup(git_path(...)) with git_pathdup(...)
  use git_path_* helper functions
  branch: add edit_description() helper
  bisect: add git_path_bisect_terms helper

builtin/commit.c

@@ -821,9 +821,9 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 					"If this is not correct, please remove the file\n"
 					"	%s\n"
 					"and try again.\n"),
-				git_path(whence == FROM_MERGE
-					 ? "MERGE_HEAD"
-					 : "CHERRY_PICK_HEAD"));
+				whence == FROM_MERGE ?
+					git_path_merge_head() :
+					git_path_cherry_pick_head());
 		}
 
 		fprintf(s->fp, "\n");