build: Replace SCons.Error with exit message

build: Replace SCons.Error with exit message

The build would crash if JAVA_HOME was not specified
because SCons.Error was not imported into the script.
This replaces the error with an exit message.

Change-Id: Ic950ae3dc0d0c3308d7bbd90ab965b17f4563f0f
Signed-off-by: George Nash <george.nash@intel.com>
Bug: https://jira.iotivity.org/browse/IOT-1745
Reviewed-on: https://gerrit.iotivity.org/gerrit/20947
Reviewed-by: Phil Coval <philippe.coval@osg.samsung.com>
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
(cherry picked from commit 369d43b707cabcf715f50ff4827670196c4f425f)
Reviewed-on: https://gerrit.iotivity.org/gerrit/21159
Reviewed-by: Mats Wichmann <mats@linux.com>