set_db_and_ix_paths and ns_server:restart are raceful which may cause couch_db to fail to start

Installing couchbase on a node after uninstalling previous installation with non-default data path gives error "Got no response from save request"
Screenshot attached.

Steps to reproduce:

On a CentOS VM:
1. rm -Rf /opt/couchbase/*
2. rm -Rf /data/*
3. sudo rpm -i couchbase-server-community_x86_64_2.0.0-beta.rpm
4. Setup the cluster with data/index path set to /data and create default bucket
5. Create a couple of documents
6. sudo rpm -e couchbase-server-2.0.0-1723
7. sudo rpm -i couchbase-server-community_x86_64_2.0.0-1888-rel.rpm
8. Setting up the cluster again with data/index path set to /data gives error and couchdb fails to initialize with below crash report

=========================CRASH REPORT=========================
crasher:
initial call: couch_db:init/1
pid: <0.5333.0>
registered_name: []
exception exit: {function_clause,
[{couch_server,'terminate/2-fun-0',
[

{<<"_replicator">>,<0.693.0>}

]},

{lists,foreach,2}

,

{gen_server,terminate,6}

,

{proc_lib,init_p_do_apply,3}

]}
in function gen_server:terminate/6
ancestors: [couch_server,couch_primary_services,couch_server_sup,
cb_couch_sup,ns_server_cluster_sup,<0.58.0>]
messages: []
links: []
dictionary: []
trap_exit: true
status: running
heap_size: 610
stack_size: 24
reductions: 376
neighbours:

Diagnostics attached.