Capture error output from ip command and check if error was caused by container dying
Merge remote-tracking branch 'upstream/bboreham-67_attach' into 67_attach
Revert "don't set pcap timeout, to prevent cpu churn"

This reverts commit b5df59660fe83fd5a5d4d3ddd23e6b084ef56465.
See issue #81
prevent CPU churn by setting long pcap timeout

pcap timeouts are a mystery. Setting the timeout to -1 used to reduce
latency, but that was before we started setting immediate mode. And it
turns out that with that timeout, pcap chews through a lot of CPU
polling its file descriptor, checking timers, etc. However, the
behaviour of setting *no* timeout is defined as, err, undefined. So
instead we set a very long timeout indeed. And loop if it expires.

Fixes #80
Merge branch 'master' into bboreham-67_attach
Refactor common code in attach/detach
Rename 'configure_container_networking' to 'attach'
Revert "don't set pcap timeout, to prevent cpu churn"

This reverts commit b5df59660fe83fd5a5d4d3ddd23e6b084ef56465.
Merge remote-tracking branch 'upstream/master' into 67_attach

Conflicts:
	pcap.go
Cosmetic
Improved comment
Merge branch '67_attach' of https://github.com/bboreham/weave into bboreham-67_attach