freetdm: check for dump enabled before writing to file

libs/freetdm/src/ftmod/ftmod_r2/ftmod_r2.c

@@ -29,6 +29,11 @@
  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Contributors: 
+ *
+ * Arnaldo Pereira <arnaldo@sangoma.com>
+ *
  */
 
 #ifdef __linux__