I don't remember why the login_form hook had to be moved up into the table (it was...

I don't remember why the login_form hook had to be moved up into the table (it was in fact always in the form), but placing it seemingly haphazard into just one of the two table cells is not useful for any of the plugins I can think of.  Moving to a table row of its own.

git-svn-id: https://svn.code.sf.net/p/squirrelmail/code/trunk/squirrelmail@11680 7612ce4b-ef26-0410-bec9-ea0150e637f0