Don't run flask dev server in threaded mode since it blocks the main loop.
Don't run flask dev server in threaded mode since it blocks the main
loop.

NOTE: This change didn't do anything in the pass since thread defaults
to True if not provided.

Plexxi/st2,nzlosh/st2,Plexxi/st2,StackStorm/st2,StackStorm/st2,nzlosh/st2,StackStorm/st2,nzlosh/st2,nzlosh/st2,StackStorm/st2,Plexxi/st2,Plexxi/st2