refactor: move flag to internal/common

cli/internal/common.go

@@ -284,6 +284,17 @@ var VerboseFlag = &cli.BoolFlag{
 	Usage:       "Show INFO messages",
 }
 
+// RC signifies the latest release candidate
+var RC bool
+
+// RCFlag chooses the latest release candidate for install
+var RCFlag = &cli.BoolFlag{
+	Name:        "rc",
+	Value:       false,
+	Destination: &RC,
+	Usage:       "Insatll the latest release candidate",
+}
+
 // SSHFailMsg is a hopefully helpful SSH failure message
 var SSHFailMsg = `
 Woops, Abra is unable to connect to connect to %s.