Try to fix `make -j <num-gt-1> check`

"Try" because couldn't reproduce it, might require new version of
automake/make, maybe its their bug.

Fixing here in hope to make life of package maintainers easier.
Merge branch 'try-to-fix-issue-with-parallel-make'

Try to fix `make -j <num-gt-1> check`.  "Try" because couldn't
reproduce it, might require new version of automake/make, maybe
it's their bug.

Fixing here in hope to make life of package maintainers easier.
Fix "gf" for directories

Broken by trailing slash change.

Thanks to filterfalse.
Remove now useless code from running:follow_link()
Use ends_with_slash() in fileops:calc_dirsize()
Use copy_str() in reset_to_default_color_scheme()
Remove now always false check from rename_file_cb
Don't add slash in navigate_to_selected_file()

This wasn't broken as ensure_file_is_selected() removes trailing
slash.
Merge branch 'fix-gf-on-dir'

It got broken after changes related to trailing slash.

Also removed some useless now code and cleaned up a couple of things.