* import-gnulib.config (modules): Use gnulib's parse-datetime
module instead of the obsolete getdate module.
(gnulib_version): Update to a recent version of gnulib.
* doc/Makefile.am (find_TEXINFOS): Update the name of the included
texinfo file accordingly.
* doc/find.texi (File Permissions): Likewise.
* find/parser.c: Include parse-datetime.h instead of getdate.h.
* po/POTFILES.in: Update the list of source files to scan for
translatable strings; include gnulib/lib/parse-datetime.y among
others.
* doc/.gitignore: Ignore parse-datetime.texi instead of
getdate.texi.