remove obsolete variable

CMake/cotire.cmake

@@ -3156,7 +3156,6 @@ if (CMAKE_SCRIPT_MODE_FILE)
 			message (STATUS "COTIRE_BUILD_TYPE=${COTIRE_BUILD_TYPE} not cotired (${COTIRE_TARGET_CONFIGURATION_TYPES})")
 		endif()
 		set (_sources "")
-		set (_sourceLocations "")
 		set (_sourcesDefinitions "")
 	endif()
 	set (_targetPreUndefs ${COTIRE_TARGET_PRE_UNDEFS})