keyboardmacosshortcutsystem-prefs
Here is the screen shot and it's not working anymore after upgrading to Yosemite
NOTE: Although if I add this shortcuts under all applications then it works.
I don't know why it's not working, wasted my time and I found on apple discussion forum that in Languages there should be only one language and that doesn't work for me.
The Service should have been saved in ~/Library/Services (~ means your home directory), so have a look for the file there. Deleting it should remove the functionality (although it should be showing up in the Services section of Keyboard Shortcuts — check to make sure it's not in a collapsed section).
You have to modify the menu title to enter the exact name of the menu command you want to add.
Best Answer
I have reported this bug to apple and it's still not being closed. I will update my answer once it's closed.
Till then you can add this shortcuts under all applications(instead of preview) then it will work.