Use CMP0048 New behavior

CMP0048 NEW behavior sets PROJECT_VERSION variables to empty strings if
project() is called with no VERSION argument. This could be a problem
for packages that set VERSION variables prior to project() because
project() would then clear them, but catkin does not do this.

Signed-off-by: Shane Loretz <sloretz@osrfoundation.org>

CMakeLists.txt

@@ -1,4 +1,5 @@
 cmake_minimum_required(VERSION 2.8.3)
+cmake_policy(SET CMP0048 NEW)
 
 set(catkin_EXTRAS_DIR ${CMAKE_CURRENT_SOURCE_DIR}/cmake)