file monitors: report MOVED only with both sides
file monitors: report MOVED only with both sides

Make sure we know the destination file before reporting a MOVED event.
Otherwise, we should just fall back to reporting it as a DELETED.

https://bugzilla.gnome.org/show_bug.cgi?id=751731

johne53/MB3Glib,cention-sany/glib,tchakabam/glib,Distrotech/glib,mzabaluev/glib,cention-sany/glib,Distrotech/glib,cention-sany/glib,gale320/glib,tamaskenez/glib,tchakabam/glib,MathieuDuponchelle/glib,mzabaluev/glib,johne53/MB3Glib,cention-sany/glib,endlessm/glib,tamaskenez/glib,mzabaluev/glib,johne53/MB3Glib,endlessm/glib,tamaskenez/glib,ieei/glib,tchakabam/glib,Distrotech/glib,gale320/glib,MathieuDuponchelle/glib,ieei/glib,ieei/glib,johne53/MB3Glib,gale320/glib,tchakabam/glib,ieei/glib,ieei/glib,cention-sany/glib,gale320/glib,Distrotech/glib,MathieuDuponchelle/glib,gale320/glib,mzabaluev/glib,johne53/MB3Glib,endlessm/glib,endlessm/glib,johne53/MB3Glib,mzabaluev/glib,tamaskenez/glib,tchakabam/glib,MathieuDuponchelle/glib,tamaskenez/glib,MathieuDuponchelle/glib,endlessm/glib,Distrotech/glib