Adding Vish as a maintainer for daemon code.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)

daemon/MAINTAINERS

@@ -3,4 +3,5 @@ Victor Vieux <vieux@docker.com> (@vieux)
 Michael Crosby <michael@crosbymichael.com> (@crosbymichael)
 Cristian Staretu <cristian.staretu@gmail.com> (@unclejack)
 Tibor Vass <teabee89@gmail.com> (@tiborvass)
+Vishnu Kannan <vishnuk@google.com> (@vishh)
 volumes.go: Brian Goff <cpuguy83@gmail.com> (@cpuguy83)