bootstrap: remove now unused gnulib modules

bootstrap: remove now unused gnulib modules

* canonicalize-lgpl: replaced by realpath()/g_canonicalize_filename()
* clock-gettime: replaced by g_get_(real|monotonic)_time
* dirname-lgpl: replaced by g_path_get_dirname()
* fclose: we aren't affected by any portability problems it fixes
* fdatasync: every platform we call fdatasync on has it present
* fsync: replaced by g_fsync()
* fnmatch: replaced by g_pattern_match()
* getcwd-lgpl: replaced by g_get_current_dir()
* gethostname: replaced by g_get_hostname()
* gettimeofday: replaced by g_get_(real|monotonic)_time
* setenv: replaced by g_setenv()
* strptime: replaced by GDateTime
* timegm: replaced by GDateTime
* unsetenv: replaced by g_unsetenv()

Reviewed-by: Fabiano Fidêncio <fidencio@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>