Update build script for RE android sample app.

Update build script for RE android sample app.

When building of RE android sample app,
we need to execute of scons build and also need additional android studio build.
With this patch, can build android sample app by only scons build.

Change-Id: Ife7142cf89993531bc15bf4b9f655090f50a1bad
Signed-off-by: KIM JungYong <jyong2.kim@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/13369
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Uze Choi <uzchoi@samsung.com>
Tested-by: Uze Choi <uzchoi@samsung.com>