HADOOP-8857. hadoop.http.authentication.signature.secret.file docs should not state that secret is randomly generated. (tucu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1438601 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9247. Parametrize Clover generateXxx properties to make them re-definable via -D in mvn calls. Contributed by Ivan A. Veselovsky.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1438698 13f79535-47bb-0310-9956-ffa450edef68