add two helper functions (schedule_add, schedule_del) and move the guts of apply_patch into a new function `patch_file'. This simplifies apply_patch and makes easier to figure out what happens. Then, drop GOT_ERR_PATCH_PATHS_DIFFER since we allow the to rename files.

otherwise got-read-patch can't parse any patch because the position indicator is at the end of file. While here fix the return too and set patchfd to -1 on error (stsp suggestion.) ok thomas, stsp

ok thomas, stsp

Use got_repo_match_object_id() instead of hand-rolled code and pick up the updated handling of reference arguments. ok stsp

This was a leftover from got_repo_resolve_commit_arg() which was superseded in commit 71a276322e39e17baf5697b5daac8e8fe6ad2ae1

Use got_repo_match_object_id() instead of hand-rolled code and pick up the updated handling of reference arguments. ok stsp

suggested by + ok naddy

Match command line arguments against references before matching object IDs. This makes it possible to use reference names that happen to match a short object ID. For example, a branch called "11ac" could not be diffed in OpenBSD src.git which happens to contain commit IDs that begin with hex digits 0x11ac. A bogus error would be reported in this situation: $ got diff master 11ac got: ambiguous object ID ok naddy

ok stsp

ok stsp

ok naddy