command.py: Add a new API triggerEvent()

This functions enables the client to request triggering specific event
from bitbake server.

(Bitbake rev: 45da6d709a69697158fae92e1c0c0a6ac8f30831)

Signed-off-by: Dongxiao Xu <dongxiao.xu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/command.py

@@ -179,6 +179,12 @@ class CommandsSync:
         """
         return bb.utils.cpu_count()
 
+    def triggerEvent(self, command, params):
+        """
+        Trigger a certain event
+        """
+        event = params[0]
+        bb.event.fire(eval(event), command.cooker.configuration.data)
 
 class CommandsAsync:
     """