etcdhttp: non-blocking sender
etcdhttp: set peer should clean up previous values
etcdhttp: simple test for peer set cleanup
etcdhttp: implment Peers.String()
etcdhttp: use peer.String() in test
Merge pull request #999 from coreos/fix_flag_set

etcdhttp: set peer should clean up previous values
raft: remove unused alwaysreadyc
Merge pull request #1027 from jonboulle/master

raft: remove unused alwaysreadyc
Merge pull request #1001 from coreos/sender

etcdhttp: non-blocking sender
*: fix a few small issues identified by go vet
Merge pull request #1030 from jonboulle/assorted

*: fix a few small issues identified by go vet
raft: prev should be set only when we sucessfully send out rd to the channel
raft: record previous state is enough
raft: set ready.st to empty state, if current state is equal to previous state
wal: do not save empty state
raft: add a newReady helper function
raft: remove extra code