The bootstrapping node will be a gossip only member, until the streaming
finishes and the node becomes NORMAL state. If during this time, the
bootstrapping node is overwhelmed with streaming, it is possible the node will
delay the update the gossip heartbeat. Be forgiving for the bootstrapping node
and do not remove it from gossip too fast. Otherwise, streaming rpc verbs will
not be resent becasue the node is not in gossip membership anymore.
Fixes#2150
Message-Id: <286d7035d854f2a48abf4e1e2e3bfcb8b22b9ca2.1494553580.git.asias@scylladb.com>