Remove dates from man pages

Counterpart to https://github.com/QubesOS/qubes-core-admin/pull/94

doc/tools/qubes-dom0-update.rst

@@ -6,8 +6,6 @@ NAME
 ====
 qubes-dom0-update - update software in dom0
 
-:Date:   2012-04-13
-
 SYNOPSIS
 ========
 | qubes-dom0-update [--action=ACTION] [--clean] [--check-only] [--gui] [<yum opts>] [<pkg list>]

doc/tools/qvm-sync-appmenus.rst

@@ -6,8 +6,6 @@ NAME
 ====
 qvm-sync-appmenus - updates desktop file templates for given StandaloneVM or TemplateVM
 
-:Date:   2012-04-11
-
 SYNOPSIS
 ========
 | qvm-sync-appmenus [options] <vm-name>