ignore: Gcov generated files

ignore: Gcov generated files

Bug: https://jira.iotivity.org/browse/IOT-1745
Change-Id: Id528461dcc6c07551554a07def899f612df97be6
Signed-off-by: Philippe Coval <philippe.coval@osg.samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/21711
Reviewed-by: Dan Mihai <Daniel.Mihai@microsoft.com>
Tested-by: Dan Mihai <Daniel.Mihai@microsoft.com>
(cherry picked from commit bd34290526ec305b6899bd303c2e3f97a76f3147)
Reviewed-on: https://gerrit.iotivity.org/gerrit/21843
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: George Nash <george.nash@intel.com>