Make atrace test app debuggable

bug:23819673

This enables its traces to be captured on user builds.

Change-Id: Ie56a6cb725e0a6e6d77ae254f0518d5bedd89409
diff --git a/hostsidetests/atrace/AtraceTestApp/AndroidManifest.xml b/hostsidetests/atrace/AtraceTestApp/AndroidManifest.xml
index a86f7f0..c460300 100644
--- a/hostsidetests/atrace/AtraceTestApp/AndroidManifest.xml
+++ b/hostsidetests/atrace/AtraceTestApp/AndroidManifest.xml
@@ -19,7 +19,7 @@
     A simple app with a tracing section to test that apps tracing signals are
     emitted by atrace.
     -->
-    <application>
+    <application android:debuggable="true"> <!-- Debuggable to enable tracing -->
         <activity android:name=".AtraceTestAppActivity">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />