config replication from ns_server node to couchdb node

Change-Id: I05973c066c6953d9f76224f5ec1148a431b20f28
make single_bucket_sup a parameter in ns_bucket_worker_sup

so the same supervisors can be reused for couchdb node

Change-Id: I8a753e5ec8cee5cfab6c581ba710e7d80d718b02
handle ns_server node rename on ns_couchdb node

Change-Id: I0212a061f9d4522a300c3cd7120679dbe0a9c14b
do not use couch_config from ns_config_default

since there will be no couch_config on ns_server node, use env variable
with default value instead

Change-Id: If4bc21d0f4bc2fef55be83e36aa7e70587a0cff8
make sure that modules for child nodes are loaded in the same order

... as for ns_server node

Change-Id: Iec5f19c11046506d18063932e8c312a40b17e675
use sockets from pool for all compaction related calls to memcached

to be able to run compaction daemon on a node without ns_memcached
server

Change-Id: I193fd60957eaa973860452436bc63e2202c4082b
use http to access couchdb on handling /couchBase urls

the existing hack with passing mochi request to the couchdb web
server won't work after couchdb will be moved to different node

Change-Id: If176e18f2e33777e4b4f9bda5601bb974be137a0
remove unnecessary opening/closing of master db from xdc_vbucket_rep

Change-Id: I4da4e696c98121297db3cbb3cc3e4f18b9a6ce5e
remove some dead code

Change-Id: I0b546b5a5cc87dc988a439914b58029848a4710c
move some functions unrelated to rdoc replication out of...

... xdc_rdoc_replication_srv.erl to the separate module

Change-Id: I08a0420b872ab16335e672ae07e95aaee7914698
wip

Change-Id: I713cd43614c717dca25988500d9ab06f77655b92