add copyright and cleanup python code

test/distrib/csharp/run_distrib_test.bat

+@rem Copyright 2016, Google Inc.
+@rem All rights reserved.
+@rem
+@rem Redistribution and use in source and binary forms, with or without
+@rem modification, are permitted provided that the following conditions are
+@rem met:
+@rem
+@rem     * Redistributions of source code must retain the above copyright
+@rem notice, this list of conditions and the following disclaimer.
+@rem     * Redistributions in binary form must reproduce the above
+@rem copyright notice, this list of conditions and the following disclaimer
+@rem in the documentation and/or other materials provided with the
+@rem distribution.
+@rem     * Neither the name of Google Inc. nor the names of its
+@rem contributors may be used to endorse or promote products derived from
+@rem this software without specific prior written permission.
+@rem
+@rem THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+@rem "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+@rem LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+@rem A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+@rem OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+@rem SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+@rem LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+@rem DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+@rem THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+@rem (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+@rem OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 @rem enter this directory
 cd /d %~dp0

tools/run_tests/distribtest_targets.py

@@ -96,7 +96,7 @@ class CSharpDistribTest(object):
       return create_jobspec(self.name,
           ['test/distrib/csharp/run_distrib_test.sh'],
           environ={'EXTERNAL_GIT_ROOT': '../../..'})
-    else:
+    elif self.platform == 'windows':
       if self.arch == 'x64':
         environ={'MSBUILD_EXTRA_ARGS': '/p:Platform=x64',
                  'DISTRIBTEST_OUTPATH': 'DistribTest\\bin\\x64\\Debug'}
@@ -105,6 +105,8 @@ class CSharpDistribTest(object):
       return create_jobspec(self.name,
           ['test\\distrib\\csharp\\run_distrib_test.bat'],
           environ=environ)
+    else:
+      raise Exception("Not supported yet.")
 
   def __str__(self):
     return self.name