HBASE-8344. Improves the assignment when node failures happen to choose the secondary RS as the new primary RS

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1491994 13f79535-47bb-0310-9956-ffa450edef68
HBASE-8700 IntegrationTestBigLinkedList can fail due to random number collision

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1492034 13f79535-47bb-0310-9956-ffa450edef68
HBASE-8706 Some improvement in snapshot (binlijin)

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1492398 13f79535-47bb-0310-9956-ffa450edef68
HBASE-8702: Make WALEditCodec pluggable

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1492407 13f79535-47bb-0310-9956-ffa450edef68
hbase-8738.  refguide, OpsMgt chapter, overhauled HBase metrics section.

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1492439 13f79535-47bb-0310-9956-ffa450edef68
hbase-8739.  book.xml  fixed typo in MapReduce chapter "spitting"

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1492455 13f79535-47bb-0310-9956-ffa450edef68
Merge branch 'trunk' of https://github.com/apache/hbase into clean
Merge branch 'clean' into fw_6295_3