…APIs.

Include the ocgrpc client handler as a dial option within grpc.Dial().
This registers the ocgrpc client handler as a service. Provide the ocgrpc
serverHandler to the grpc statsHandler when creating a new grpc server.

Also, edit the Gopkg.toml file to update the following package versions
for successful compilation,
 1. "github.com/coreos/etcd":     v3.2.9 -> v3.3.8
 2. "github.com/golang/protobuf": v1.0.0 -> v1.1.0
 3. "google.golang.org/grpc":     v1.0.4 -> v1.13.0

Signed-off-by: Sridhar Seshasayee <sseshasa@redhat.com>

Pass the original context to the runStepOn() function so that it can be
used by the opensensus grpc plugin to trace the calls on other nodes in
the gluster cluster. Also, append the requestID to the span info in
addition to the associated function name so that the operation can be
identified on the tracing UI application.

Signed-off-by: Sridhar Seshasayee <sseshasa@redhat.com>