HDFS-4484. libwebhdfs compilation broken with gcc 4.6.2. Contributed by Colin Patrick McCabe.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1455782 13f79535-47bb-0310-9956-ffa450edef68
(cherry picked from commit 94aa841466c2eb2b577bfc62e7fd4003f2ca7d18)
make proto buf changes; fix TestCachingStrategy

Signed-off-by: Colin Patrick McCabe <cmccabe@cloudera.com>
FileInputStreamCache: add maxExpiryTimeMs

Signed-off-by: Colin Patrick McCabe <cmccabe@cloudera.com>
revise RPCs, add MlockManager

Signed-off-by: Colin Patrick McCabe <cmccabe@cloudera.com>
implement real (native) MLockManager

Signed-off-by: Colin Patrick McCabe <cmccabe@cloudera.com>