X wcfs: Take $WENDELIN_CORE_WCFS_OPTIONS into account not only from under join

This way when wcfs is started via _start it also takes default options
into account. Noticid while running test_join with
$WENDELIN_CORE_WCFS_OPTIONS set and not propagated to spawned wcfs.

wcfs/__init__.py

@@ -58,7 +58,7 @@ The following environment variables can be used to control wcfs.py client:
       no        join: don't spawn wcfs server unless explicitly requested via autostart=True
 
   $WENDELIN_CORE_WCFS_OPTIONS
-      ""        join: additional options to pass to wcfs server if one is spawned
+      ""        additional options to pass to wcfs server when spawned it
 """
 
 from __future__ import print_function, absolute_import
@@ -207,8 +207,7 @@ def join(zurl, autostart=_default_autostart()): # -> WCFS
         # start wcfs with telling it to automatically exit when there is no client activity.
         # XXX race window if external process starts after ^^^ check
         # TODO -> fs-level locking
-        optv_extra = os.environ.get("WENDELIN_CORE_WCFS_OPTIONS", "").split()
-        return _start(zurl, "-autoexit", *optv_extra)
+        return _start(zurl, "-autoexit")
 
 
 # _start starts wcfs server for ZODB @ zurl.
@@ -219,6 +218,9 @@ def _start(zurl, *optv):    # -> WCFS
     mntpt = _mntpt_4zurl(zurl)
     log.info("wcfs: starting for %s ...", zurl)
 
+    optv_defaults = os.environ.get("WENDELIN_CORE_WCFS_OPTIONS", "").split()
+    optv = tuple(optv_defaults) + optv
+
     # XXX errctx "wcfs: start"
 
     # spawn wcfs and wait till filesystem-level access to it is ready
@@ -341,6 +343,8 @@ def _mkdir_p(path, mode=0777): # -> created(bool)
 def serve(zurl, optv, exec_=False):
     mntpt = _mntpt_4zurl(zurl)
 
+    # XXX take $WENDELIN_CORE_WCFS_OPTIONS into account?
+
     # try opening .wcfs - it is an error if we can do it.
     # XXX -> option to wcfs itself to verify wcfs/something is already mounted?
     try: