Valgrind reports quite a lot of discarded memory inside apply.
Fix them, audit and document the buffer ownership rules.
By Junio C Hamano (8) and Jared Hance (1)
* jh/apply-free-patch:
apply: document buffer ownership rules across functions
apply: tighten constness of line buffer
apply: drop unused macro
apply: free unused fragments for submodule patch
apply: free patch->result
apply: release memory for fn_table
apply: free patch->{def,old,new}_name fields
apply: rename free_patch() to free_patch_list()
apply: do not leak patches and fragments