Update commons-collections test dependency to 3.2.2 (elastic#52808) (elastic#52817)

This is only a test dependency but it trips scanners so upgrade to
3.2.2 which doesn't suffer from the issues mentioned in i.e.
https://snyk.io/vuln/SNYK-JAVA-COMMONSCOLLECTIONS-472711

Author: jkakavas

x-pack/plugin/security/build.gradle

@@ -102,7 +102,7 @@ dependencies {
   testCompile('org.apache.directory.api:api-ldap-extras-codec:1.0.0')
   testCompile('org.apache.directory.api:api-ldap-extras-codec-api:1.0.0')
   testCompile('commons-pool:commons-pool:1.6')
-  testCompile('commons-collections:commons-collections:3.2')
+  testCompile('commons-collections:commons-collections:3.2.2')
   testCompile('org.apache.mina:mina-core:2.0.17')
   testCompile('org.apache.directory.api:api-util:1.0.1')
   testCompile('org.apache.directory.api:api-i18n:1.0.1')