Update user agent string to include OS and Python version info

Author: Mike Kistler

watson_developer_cloud/watson_developer_cloud_service.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import json as json_import
+import platform
 import os
 import requests
 import sys
@@ -103,6 +104,12 @@ def __init__(self, vcap_services_name, url, username=None, password=None,
         self.password = None
         self.default_headers = None
 
+        user_agent_string = 'watson-apis-python-sdk-' + __version__ # SDK version
+        user_agent_string += ' ' + platform.system() # OS
+        user_agent_string += ' ' + platform.release() # OS version
+        user_agent_string += ' ' + platform.python_version() # Python version
+        self.user_agent_header = {'user-agent': user_agent_string}
+
         if x_watson_learning_opt_out:
             self.default_headers = {'x-watson-learning-opt-out': 'true'}
 
@@ -273,8 +280,7 @@ def request(self, method, url, accept_json=False, headers=None,
 
         input_headers = _remove_null_values(headers) if headers else {}
 
-        headers = CaseInsensitiveDict(
-            {'user-agent': 'watson-developer-cloud-python-' + __version__})
+        headers = CaseInsensitiveDict(self.user_agent_header)
         if self.default_headers is not None:
             headers.update(self.default_headers)
         if accept_json: