fix copyrights

tools/jenkins/build_and_run_docker.sh

 #!/bin/bash
-# Copyright 2015-2016, Google Inc.
+# Copyright 2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without

tools/jenkins/docker_run.sh

 #!/bin/bash
-# Copyright 2015, Google Inc.
+# Copyright 2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without

tools/jenkins/grpc_artifact_linux_x64/Dockerfile

-# Copyright 2015-2016, Google Inc.
+# Copyright 2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without

tools/jenkins/grpc_artifact_linux_x86/Dockerfile

-# Copyright 2015-2016, Google Inc.
+# Copyright 2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without

tools/run_tests/build_artifact_csharp.sh

 #!/bin/bash
-# Copyright 2015-2016, Google Inc.
+# Copyright 2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without