fix #1 set self.session_timeout in init

pyotrs/lib.py

@@ -489,7 +489,9 @@ class Client(object):
 
         if not session_timeout:
             self.session_timeout = 28800  # 8 hours is OTRS default
-
+        else:
+            self.session_timeout = session_timeout
+            
         self.https_verify = https_verify
 
         # dummy initialization