File "has unexpected contents" error when sideloading Android 5.0 OTA zip file

I have a Nexus 7 (2013) (wifi) and am trying to update the software to Android 5.0. When I try to sideload, I get this error: Installing update... mount: failed to mount /dev/block/platform/msm.sdcc.1/by-name/system at /system: Invalid argument Verifying current system... "/system/app/Drive.apk" has unexpected contents. E: Error in /tmp/update.zip (Status 7) Installation aborted. How I did it: I placed the OTA file in sdk/platform-tools folder. Then I opened up a command prompt and typed in adb sideload 5a0f7a47588c268c239e58cf568823c6637c5af1.signed-razor-LRX21P-from-KTU84P.5a0f7a47.zip and I got that error. What did I do wrong?