Refactoring the TB_LOG flag for Android builds.

Refactoring the TB_LOG flag for Android builds.

The TB_LOG flag on Android should not be defined with '-D'.
When using compilers for an arch type other than armeabi
or x86 (reproducable for sure on armeabi-v7a), the definition
for TB_LOG ended up being "-D-DTB_LOG".

This issue & solution was raised by an outside contributor
Anton Spaans <flyingdutchie@gmail.com>.

Change-Id: I9f8caeec37e241fb62772bc8d9f9628f87ff0eb0
Signed-off-by: Joseph Morrow <joseph.l.morrow@intel.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/1152
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Erich Keane <erich.keane@intel.com>