t7005-editor: get rid of the SPACES_IN_FILENAMES prereq

t7005-editor: get rid of the SPACES_IN_FILENAMES prereq

The last two tests 'editor with a space' and 'core.editor with a
space' in 't7005-editor.sh' need the SPACES_IN_FILENAMES prereq to
ensure that they are only run on filesystems that allow, well, spaces
in filenames.  However, we have been putting a space in the name of
the trash directory for just over a decade now, so we wouldn't be able
to run any of our tests on such a filesystem in the first place.

This prereq is therefore unnecessary, remove it.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>