Code clean-up to remove unused function parameters.
* jk/unused-fixes:
xdiff: drop unused mmfile parameters from xdl_do_patience_diff()
reflog: assert PARSE_OPT_NONEG in parse-options callbacks
reftable: drop unused parameter from reader_seek_linear()
verify_one_sparse(): drop unused parameters
match_pathname(): drop unused "flags" parameter
log-tree: drop unused commit param in remerge_diff()
xdiff: drop unused mmfile parameters from xdl_do_histogram_diff()