Update logging format of the driver

[leakingtapan]

This enables printing actual values inside request instead of address of the value

Testing
Verified log message with driver example:

I0102 20:46:05.600336       1 driver.go:98] Listening for connections on address: &net.UnixAddr{Name:"/csi/csi.sock", Net:"unix"}
I0102 20:46:05.916391       1 node.go:123] NodeGetId: called with args
I0102 20:47:22.084429       1 node.go:99] NodeGetCapabilities: called with args
I0102 20:47:22.085540       1 node.go:99] NodeGetCapabilities: called with args
I0102 20:47:22.091407       1 node.go:43] NodePublishVolume: called with args volume_id:"fs-ff2a9557" target_path:"/var/lib/kubelet/pods/81923b27-0ecf-11e9-bace-06ec5779c508/volumes/kubernetes.io~csi/efs-pv/mount" volume_capability:<mount:<fs_type:"ext4" > access_mode:<mode:SINGLE_NODE_WRITER > >
I0102 20:47:22.091529       1 node.go:67] NodePublishVolume: creating dir /var/lib/kubelet/pods/81923b27-0ecf-11e9-bace-06ec5779c508/volumes/kubernetes.io~csi/efs-pv/mount
I0102 20:47:22.091552       1 node.go:72] NodePublishVolume: mounting fs-ff2a9557:/ at /var/lib/kubelet/pods/81923b27-0ecf-11e9-bace-06ec5779c508/volumes/kubernetes.io~csi/efs-pv/mount