Revert "Upgrade to Ehcache 2.10.5" in 2.0 as well

See gh-13056

spring-boot-project/spring-boot-dependencies/pom.xml

@@ -54,7 +54,7 @@
 		<derby.version>10.14.1.0</derby.version>
 		<dom4j.version>1.6.1</dom4j.version>
 		<dropwizard-metrics.version>3.2.6</dropwizard-metrics.version>
-		<ehcache.version>2.10.5</ehcache.version>
+		<ehcache.version>2.10.4</ehcache.version>
 		<ehcache3.version>3.5.2</ehcache3.version>
 		<embedded-mongo.version>2.0.3</embedded-mongo.version>
 		<flyway.version>5.0.7</flyway.version>