Make perf builds profileable.

app/src/perf/AndroidManifest.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="org.thoughtcrime.securesms">
+
+    <application>
+        <profileable android:shell="true" />
+    </application>
+</manifest>