Fixed bug in simnet 'shell' command
Fixed bug in simnet 'shell' command

-- Fixed bug in simnet tool that resulted in the 'shell' command failing when linux
decided to assign ids to network namespaces.  This caused a change in the output
of the 'ip netns list' command which simnet wasn't prepared to parse.

openweave/openweave-core,openweave/openweave-core,openweave/openweave-core,openweave/openweave-core,openweave/openweave-core,openweave/openweave-core