Pass the storage engine option to RPC workers

COUCHDB-3287
diff --git a/src/fabric_db_create.erl b/src/fabric_db_create.erl
index a7f4ed9..3685398 100644
--- a/src/fabric_db_create.erl
+++ b/src/fabric_db_create.erl
@@ -28,7 +28,7 @@
             {error, file_exists};
         false ->
             {Shards, Doc} = generate_shard_map(DbName, Options),
-            CreateShardResult = create_shard_files(Shards),
+            CreateShardResult = create_shard_files(Shards, Options),
             case CreateShardResult of
             enametoolong ->
                 {error, {database_name_too_long, DbName}};
@@ -64,12 +64,12 @@
         % the DB already exists, and may have a different Suffix
         ok;
     {not_found, _} ->
-        Doc = make_document(Shards, Suffix)
+        Doc = make_document(Shards, Suffix, Options)
     end,
     {Shards, Doc}.
 
-create_shard_files(Shards) ->
-    Workers = fabric_util:submit_jobs(Shards, create_db, []),
+create_shard_files(Shards, Options) ->
+    Workers = fabric_util:submit_jobs(Shards, create_db, [Options]),
     RexiMon = fabric_util:create_monitors(Shards),
     try fabric_util:recv(Workers, #shard.ref, fun handle_message/3, Workers) of
     {error, file_exists} ->
@@ -155,7 +155,7 @@
         end
     end.
 
-make_document([#shard{dbname=DbName}|_] = Shards, Suffix) ->
+make_document([#shard{dbname=DbName}|_] = Shards, Suffix, Options) ->
     {RawOut, ByNodeOut, ByRangeOut} =
     lists:foldl(fun(#shard{node=N, range=[B,E]}, {Raw, ByNode, ByRange}) ->
         Range = ?l2b([couch_util:to_hex(<<B:32/integer>>), "-",
@@ -164,12 +164,19 @@
         {[[<<"add">>, Range, Node] | Raw], orddict:append(Node, Range, ByNode),
             orddict:append(Range, Node, ByRange)}
     end, {[], [], []}, Shards),
-    #doc{id=DbName, body = {[
-        {<<"shard_suffix">>, Suffix},
-        {<<"changelog">>, lists:sort(RawOut)},
-        {<<"by_node">>, {[{K,lists:sort(V)} || {K,V} <- ByNodeOut]}},
-        {<<"by_range">>, {[{K,lists:sort(V)} || {K,V} <- ByRangeOut]}}
-    ]}}.
+    EngineProp = case couch_util:get_value(engine, Options) of
+        E when is_binary(E) -> [{<<"engine">>, E}];
+        _ -> []
+    end,
+    #doc{
+        id = DbName,
+        body = {[
+            {<<"shard_suffix">>, Suffix},
+            {<<"changelog">>, lists:sort(RawOut)},
+            {<<"by_node">>, {[{K,lists:sort(V)} || {K,V} <- ByNodeOut]}},
+            {<<"by_range">>, {[{K,lists:sort(V)} || {K,V} <- ByRangeOut]}}
+        ] ++ EngineProp}
+    }.
 
 db_exists(DbName) -> is_list(catch mem3:shards(DbName)).
 
diff --git a/src/fabric_rpc.erl b/src/fabric_rpc.erl
index 556d289..9840c9f 100644
--- a/src/fabric_rpc.erl
+++ b/src/fabric_rpc.erl
@@ -16,7 +16,7 @@
 -export([open_doc/3, open_revs/4, get_doc_info/3, get_full_doc_info/3,
     get_missing_revs/2, get_missing_revs/3, update_docs/3]).
 -export([all_docs/3, changes/3, map_view/4, reduce_view/4, group_info/2]).
--export([create_db/1, delete_db/1, reset_validation_funs/1, set_security/3,
+-export([create_db/2, delete_db/1, reset_validation_funs/1, set_security/3,
     set_revs_limit/3, create_shard_db_doc/2, delete_shard_db_doc/2]).
 -export([get_all_security/2, open_shard/2]).
 -export([compact/1, compact/2]).
@@ -144,8 +144,8 @@
     #mrargs{skip=Skip, limit=Limit}=Args,
     Args#mrargs{skip=0, limit=Skip+Limit}.
 
-create_db(DbName) ->
-    rexi:reply(case couch_server:create(DbName, []) of
+create_db(DbName, Options) ->
+    rexi:reply(case couch_server:create(DbName, Options) of
     {ok, _} ->
         ok;
     Error ->