Commit 97b67e4 introduced some changes to the
BugData class: the 'attachment' column was renamed to 'attachment_count'. This
change was not cascaded everywhere, which resulted in the column not being
displayed by default (as the now-invalid column named 'attachment' was
automatically removed)

This then hid the fact that $g_show_attachment_indicator was actually not
working as advertised, i.e. the attachments column is always displayed; when
ON the field contains the paperclip bitmap, and when OFF the actual number of
attachments for the corresponding issue.

Affects issue #13276

This commit also removes some trailing whitespace

The list now matches what is actually available in the manage columns pages

file_can_view_bug_attachments does check for allow_view_own_attachments

Following discussion with dhx on IRC today, this setting is not necessary.

There is no point or advantage in displaying a paperclip bitmap as opposed to
the actual number of attachments; furthermore, the option was inconsistently
used, in one instance it was actually hiding the attachments column completely

Affects issue #13276

Commit also removes trailing whitespace in columns_api.php

Conflicts:
	config_defaults_inc.php