(PUP-11763) Converts ctime/mtime to string

Prior to this commit, Puppet's file type returned a file's ctime
and mtime (created and modified times) as Time objects. This commit
converts those to Strings instead to alleviate issues when those
values needed to be used in formats that don't understand Time
objects (e.g. YAML).

Author: mhashizume

lib/puppet/type/file/ctime.rb

@@ -10,7 +10,7 @@ def retrieve
       if stat
         current_value = stat.ctime
       end
-      current_value
+      current_value.to_s
     end
 
     validate do |val|

lib/puppet/type/file/mtime.rb

@@ -9,7 +9,7 @@ def retrieve
       if stat
         current_value = stat.mtime
       end
-      current_value
+      current_value.to_s
     end
 
     validate do |val|

spec/unit/type/file/ctime_spec.rb

@@ -15,7 +15,7 @@
     @resource[:audit] = [:ctime]
 
     # this .to_resource audit behavior is magical :-(
-    expect(@resource.to_resource[:ctime]).to eq(Puppet::FileSystem.stat(@filename).ctime)
+    expect(@resource.to_resource[:ctime]).to eq(Puppet::FileSystem.stat(@filename).ctime.to_s)
   end
 
   it "should return absent if auditing an absent file" do

spec/unit/type/file/mtime_spec.rb

@@ -15,7 +15,7 @@
     @resource[:audit] = [:mtime]
 
     # this .to_resource audit behavior is magical :-(
-    expect(@resource.to_resource[:mtime]).to eq(Puppet::FileSystem.stat(@filename).mtime)
+    expect(@resource.to_resource[:mtime]).to eq(Puppet::FileSystem.stat(@filename).mtime.to_s)
   end
 
   it "should return absent if auditing an absent file" do