[packages] dovecot: update to 2.2.8

Signed-off-by: Peter Wagner <tripolar@gmx.at>


git-svn-id: svn://svn.openwrt.org/openwrt/packages@38877 3c298f89-4303-0410-b956-a3cf2f4a3e73
Merge branch 'master' of git://git.openwrt.org/packages