manifest: remove PerformanceControl

R.I.P.

Change-Id: I800dabc5a4f40cefdeddbf2cd329a46e11b82c36

omni-default.xml

@@ -29,7 +29,6 @@
   <project path="packages/apps/OmniStyle" name="android_packages_apps_OmniStyle" remote="omnirom" revision="android-7.1" />
   <project path="packages/apps/OmniSwitch" name="android_packages_apps_OmniSwitch" remote="omnirom" revision="android-7.1" />
   <project path="packages/apps/OpenDelta" name="android_packages_apps_OpenDelta" remote="omnirom" revision="android-7.1" />
-  <project path="packages/apps/PerformanceControl" name="android_packages_apps_PerformanceControl" remote="omnirom" revision="android-7.1" />
   <project path="vendor/omni" name="android_vendor_omni2" remote="omnirom" revision="android-7.1" />
 
 </manifest>