Add can_seek
Add can_seek

Original git commit by Alexander Larsson <alex@localhost.localdomain> at 1163513085 +0100

svn path=/trunk/; revision=147

thiblahute/gvfs,xkahn/gvfs-cmis,xkahn/gvfs-cmis,thiblahute/gvfs,xkahn/gvfs-cmis,gicmo/gvfs,cpatulea/gvfs,cpatulea/gvfs,gicmo/gvfs,philipl/gvfs,halfline/gvfs,philipl/gvfs,gicmo/gvfs,halfline/gvfs,xkahn/gvfs-cmis,gicmo/gvfs,philipl/gvfs,halfline/gvfs