Upgrade to Hystrix v1.4.20

pom.xml

@@ -28,7 +28,7 @@
 		<archaius.version>0.6.5</archaius.version>
 		<eureka.version>1.3.4</eureka.version>
 		<feign.version>8.11.0</feign.version>
-		<hystrix.version>1.4.18</hystrix.version>
+		<hystrix.version>1.4.20</hystrix.version>
 		<ribbon.version>2.1.0</ribbon.version>
 		<servo.version>0.10.0</servo.version>
 		<zuul.version>1.1.0-rc.1</zuul.version>
@@ -356,6 +356,12 @@
 				<groupId>com.netflix.hystrix</groupId>
 				<artifactId>hystrix-metrics-event-stream</artifactId>
 				<version>${hystrix.version}</version>
+				<exclusions>
+					<exclusion>
+						<groupId>javax.servlet</groupId>
+						<artifactId>servlet-api</artifactId>
+					</exclusion>
+				</exclusions>
 			</dependency>
 			<dependency>
 				<groupId>com.netflix.hystrix</groupId>