Add back serializiation of last opened time

src/packages/fuzzy-finder/lib/fuzzy-finder.coffee

@@ -31,7 +31,12 @@ module.exports =
     @projectPaths = null
 
   serialize: ->
-    @fuzzyFinderView?.getOpenedPaths()
+    if @fuzzyFinderView?
+      paths = {}
+      for editSession in project.getEditSessions()
+        path = editSession.getPath()
+        paths[path] = editSession.lastOpened if path?
+      paths
 
   createView:  ->
     unless @fuzzyFinderView

src/packages/fuzzy-finder/spec/fuzzy-finder-spec.coffee

@@ -145,6 +145,7 @@ describe 'FuzzyFinder', ->
 
           atom.deactivatePackage('fuzzy-finder')
           states = _.map atom.getPackageState('fuzzy-finder'), (path, time) -> [ path, time ]
+          expect(states.length).toBe 3
           states = _.sortBy states, (path, time) -> -time
 
           paths = [ 'sample-with-tabs.coffee', 'sample.txt', 'sample.js' ]