[dev_finder] Change flags to conform to standards.

DX-1018 #done

TEST=None

Change-Id: Icef02b18c3d3af6712d03f325f61643ae04f8178
diff --git a/cmd/dev_finder/common.go b/cmd/dev_finder/common.go
index 46d382a..492d6bf 100644
--- a/cmd/dev_finder/common.go
+++ b/cmd/dev_finder/common.go
@@ -70,7 +70,7 @@
 	f.IntVar(&cmd.mdnsPort, "port", 5353, "The port your mDNS servers operate on.")
 	f.IntVar(&cmd.timeout, "timeout", 2000, "The number of milliseconds before declaring a timeout.")
 	f.BoolVar(&cmd.localResolve, "local", false, "Returns the address of the interface to the host when doing service lookup/domain resolution.")
-	f.IntVar(&cmd.deviceLimit, "device_limit", 0, "Exits before the timeout at this many devices per resolution (zero means no limit).")
+	f.IntVar(&cmd.deviceLimit, "device-limit", 0, "Exits before the timeout at this many devices per resolution (zero means no limit).")
 }
 
 // Extracts the IP from its argument, returning an error if the type is unsupported.
diff --git a/cmd/dev_finder/list.go b/cmd/dev_finder/list.go
index 28bc049..65afc11 100644
--- a/cmd/dev_finder/list.go
+++ b/cmd/dev_finder/list.go
@@ -43,7 +43,7 @@
 
 func (cmd *listCmd) SetFlags(f *flag.FlagSet) {
 	cmd.SetCommonFlags(f)
-	f.StringVar(&cmd.domainFilter, "domain_filter", "", "When using the \"list\" command, returns only devices that match this domain name.")
+	f.StringVar(&cmd.domainFilter, "domain-filter", "", "When using the \"list\" command, returns only devices that match this domain name.")
 	f.BoolVar(&cmd.fullInfo, "full", false, "Print device address and domain")
 }