Added random test for ParentConstantScoreQuery
property file for client build projects

this property file contains url information for s3 elasticsearch server
bits retrieval on master, 0.90 branch
add nightly es_node_mode radomization
jenkin scripts modification

1) client_tests_url, switch to JDK6
2) build_ranodmization, add jvm options randomization
AckTests: more assertAcked and added common method to retrieve local cluster state
Fix typo in MockRamDirectoryService name
Prevent modification or deletion of repositories while snapshots are running
Fix possible NPE in snapshot service if a shard doesn't have primary