tizen: Set variable as version

This will be useful for creating snapshot versions ie:
1.3.0+99+1.3.1+RC5~B4DC0DE

Bug: https://jira.iotivity.org/browse/IOT-1745
Change-Id: Ib95ee7c53cc226e411bacc03313ffd6829b7e7d1
Signed-off-by: Philippe Coval <philippe.coval@osg.samsung.com>

tools/tizen/iotivity.spec

 Name: iotivity
-Version: 1.3.1
-Release: 0
+Version: %{!?version:1.3.1}%{?version}
+Release: %{!?release:0}%{?release}
 Summary: IoT Connectivity sponsored by the OCF
 Group: Network & Connectivity / IoT Connectivity
 License: Apache-2.0 and BSD-2-Clause and (MIT or BSL-1.0) and MIT