Update to Spring 4.3.4.RELEASE

Fixes gh-4123

build.gradle

@@ -27,7 +27,7 @@ allprojects {
 
 	ext.releaseBuild = version.endsWith('RELEASE')
 	ext.snapshotBuild = version.endsWith('SNAPSHOT')
-	ext.springVersion = '4.3.3.RELEASE'
+	ext.springVersion = '4.3.4.RELEASE'
 	ext.springLdapVersion = '2.2.0.RC1'
 
 	group = 'org.springframework.security'