Fix typo

Closes gh-3416

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/writer/DropwizardMetricWriter.java

@@ -94,16 +94,16 @@ public class DropwizardMetricWriter implements MetricWriter {
 		else {
 			final double gauge = value.getValue().doubleValue();
 			// Ensure we synchronize to avoid another thread pre-empting this thread after
-			// remove causing an error in CodaHale metrics
-			// NOTE: CodaHale provides no way to do this atomically
-			synchronized (getGuageLock(name)) {
+			// remove causing an error in Dropwizard Metrics
+			// NOTE: Dropwizard Metrics provides no way to do this atomically
+			synchronized (getGaugeLock(name)) {
 				this.registry.remove(name);
 				this.registry.register(name, new SimpleGauge(gauge));
 			}
 		}
 	}
 
-	private Object getGuageLock(String name) {
+	private Object getGaugeLock(String name) {
 		Object lock = this.gaugeLocks.get(name);
 		if (lock == null) {
 			Object newLock = new Object();