Android: Set ANDROID_SDK_ROOT environment variable

Needed by androiddeployqt

Task-number: QTCREATORBUG-10289

Change-Id: I64abef7278fab5c9261f9f954af416410f69ce0d
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>

src/plugins/android/androidtoolchain.cpp

@@ -124,6 +124,7 @@ void AndroidToolChain::addToEnvironment(Environment &env) const
     if (!javaHome.isEmpty() && QFileInfo(javaHome).exists())
         env.set(QLatin1String("JAVA_HOME"), javaHome);
     env.set(QLatin1String("ANDROID_HOME"), AndroidConfigurations::instance().config().sdkLocation.toString());
+    env.set(QLatin1String("ANDROID_SDK_ROOT"), AndroidConfigurations::instance().config().sdkLocation.toString());
 }
 
 bool AndroidToolChain::operator ==(const ToolChain &tc) const