Fortunately, there's a way to hide the people from your Google+ circles. Google+ has a feature called "your circles" which lets you select which circles you share with. For example, you can add the "Friends" and "Family" circles and quickly share your posts with your favorite circles without having to select them all the time.
"When you share posts, photos, profile data, and other things with 'Your circles,' you're sharing with all of your circles, except the ones you're just following (they're unchecked in this list)," explains Google.
The good news is that Google Contacts only includes the people from "your circles", so you can customize "your circles" and uncheck all of them. This way, the "all contacts" section will only include your contacts. The downside is that the "your circles" option from Google+ will no longer be useful, but you can always manually select your circles.