Android: add --release parameter when building for Release.

Change-Id: Ie5875f076039b25f03f9a872a85ca7c249659dc8
Reviewed-by: Daniel Teske <daniel.teske@digia.com>

src/plugins/qmakeandroidsupport/qmakeandroidbuildapkstep.cpp

@@ -233,6 +233,9 @@ bool QmakeAndroidBuildApkStep::init()
     if (m_verbose)
         arguments << QLatin1String("--verbose");
 
+    if (buildConfiguration()->buildType() == ProjectExplorer::BuildConfiguration::Release)
+        arguments << QLatin1String("--release");
+
     if (m_signPackage) {
         arguments << QLatin1String("--sign")
                   << m_keystorePath.toString()