Define compiler properties locally so can potentially update to later version of project pom

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/branches/4.3.x@1578706 13f79535-47bb-0310-9956-ffa450edef68
Fixup comments:
- remind readers not to omit the Locale
- avoid possible false positives when searching for missing Locales

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/branches/4.3.x@1578707 13f79535-47bb-0310-9956-ffa450edef68