Android: Add missing reset of state variable

The m_skipBuilding variable in AndroidBuildApkStep needs to be re-
calculated on every call to init().
Also add some debug statements that will help us find out why it becomes
true in the first place.

Task-number: QTCREATORBUG-23572
Change-Id: I058b58cf0e511557d1fad7e5bd03048a7d8b9c69
Reviewed-by: BogDan Vatra <bogdan@kdab.com>

src/plugins/android/androidbuildapkstep.cpp

@@ -230,9 +230,11 @@ bool AndroidBuildApkStep::init()
         m_inputFile = node->data(Constants::AndroidDeploySettingsFile).toString();
 
     if (m_inputFile.isEmpty()) {
+        qCDebug(buildapkstepLog) << "no input file" << rc << node << buildKey;
         m_skipBuilding = true;
         return true;
     }
+    m_skipBuilding = false;
 
     if (m_buildTargetSdk.isEmpty()) {
         emit addOutput(tr("Android build SDK not defined. Check Android settings."),