Replace for loops with foreach loops

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/email/trunk@1507610 13f79535-47bb-0310-9956-ffa450edef68
Simply assertion

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/email/trunk@1507611 13f79535-47bb-0310-9956-ffa450edef68