Upgrade HTTP components to 4.3.4

Closes #1153

spring-boot-dependencies/pom.xml

@@ -68,7 +68,7 @@
 		<hibernate-jpa-api.version>1.0.1.Final</hibernate-jpa-api.version>
 		<hibernate-validator.version>5.0.3.Final</hibernate-validator.version>
 		<hikaricp.version>1.3.8</hikaricp.version>
-		<httpclient.version>4.3.3</httpclient.version>
+		<httpclient.version>4.3.4</httpclient.version>
 		<httpasyncclient.version>4.0.1</httpasyncclient.version>
 		<hornetq.version>2.4.1.Final</hornetq.version>
 		<hsqldb.version>2.3.2</hsqldb.version>