[master] fix msqg socket file problem

this problem surfaced when 1246 got merged; the ModuleCCSession start in bind10 actually relied on some environment variable leaking out (which 1246 fixed).
This change makes it an explicit optional argument to ModuleCCSession (which can still be overridden by the environment variable)

src/bin/bind10/bind10_src.py.in

@@ -503,7 +503,8 @@ class BoB:
         self.log_starting("ccsession")
         self.ccs = isc.config.ModuleCCSession(SPECFILE_LOCATION, 
                                       self.config_handler,
-                                      self.command_handler)
+                                      self.command_handler,
+                                      socket_file = self.msgq_socket_file)
         self.ccs.start()
         self.log_started()
 

src/lib/python/isc/config/ccsession.py

@@ -143,7 +143,9 @@ class ModuleCCSession(ConfigData):
        callbacks are called when 'check_command' is called on the
        ModuleCCSession"""
        
-    def __init__(self, spec_file_name, config_handler, command_handler, cc_session=None, handle_logging_config=True):
+    def __init__(self, spec_file_name, config_handler, command_handler,
+                 cc_session=None, handle_logging_config=True,
+                 socket_file = None):
         """Initialize a ModuleCCSession. This does *NOT* send the
            specification and request the configuration yet. Use start()
            for that once the ModuleCCSession has been initialized.
@@ -165,6 +167,12 @@ class ModuleCCSession(ConfigData):
            logger manager when the logging configuration gets updated.
            The module does not need to do anything except intializing
            its loggers, and provide log messages. Defaults to true.
+
+           socket_file: If cc_session was none, this optional argument
+           specifies which socket file to use to connect to msgq. It
+           will be overridden by the environment variable
+           MSGQ_SOCKET_FILE. If none, and no environment variable is
+           set, it will use the system default.
         """
         module_spec = isc.config.module_spec_from_file(spec_file_name)
         ConfigData.__init__(self, module_spec)
@@ -175,7 +183,7 @@ class ModuleCCSession(ConfigData):
         self.set_command_handler(command_handler)
 
         if not cc_session:
-            self._session = Session()
+            self._session = Session(socket_file)
         else:
             self._session = cc_session
         self._session.group_subscribe(self._module_name, "*")