Fix some crashes in simple file enumerator
Fix some crashes in simple file enumerator

Original git commit by Alexander Larsson <alex@greebo.(none)> at 1159803538 +0200

svn path=/trunk/; revision=62

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