Better messaging for missing volume components on host to perform mount

pkg/volume/flocker/flocker.go

@@ -210,6 +210,14 @@ func (b *flockerVolumeMounter) GetAttributes() volume.Attributes {
 		SupportsSELinux: false,
 	}
 }
+
+// Checks prior to mount operations to verify that the required components (binaries, etc.)
+// to mount the volume are available on the underlying node.
+// If not, it returns an error
+func (b *flockerVolumeMounter) CanMount() error {
+	return nil
+}
+
 func (b *flockerVolumeMounter) GetPath() string {
 	return getPath(b.podUID, b.volName, b.plugin.host)
 }