android: show stack trace if gradle fails

android: show stack trace if gradle fails

When gradle fails for whatever reason it does not show so many
information in most situations. This patch makes it show a complete
stack trace which makes identifying the issue much easier.

Change-Id: I943d8fbbb9b8c1e4a068330e6d1cd6edc4954d6c
Signed-off-by: Hauke Mehrtens <hauke.mehrtens@lantiq.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/2219
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Jon A. Cruz <jonc@osg.samsung.com>