Refactored android default ArchType check in SConscript.

Refactored android default ArchType check in SConscript.

According to SCons' wiki, checking strings should be done with "==" and
not "is". "is" is to be used for checking against the ID value for a
value and not the value, while "==" checks against the value.

Change-Id: I28710e324d998098cd22bb615a03c388f6903f18
Signed-off-by: Joseph Morrow <joseph.l.morrow@intel.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/1170
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Erich Keane <erich.keane@intel.com>