store: initialize vfs field first to use it for initialization of others

This patch initializes "vfs" field in the constructor of each store
classes to use it for initialization of others.

In this patch, "self.vfs.base" is used to initialize "self.path",
because redo join of path components for "self.path" is redundant.

mercurial/store.py

@@ -291,9 +291,9 b' def _calcmode(path):'
 class basicstore(object):
     '''base class for local repository stores'''
     def __init__(self, path, vfstype):
-        self.path = path
+        vfs = vfstype(path)
+        self.path = vfs.base
         self.createmode = _calcmode(path)
-        vfs = vfstype(self.path)
         vfs.createmode = self.createmode
         self.vfs = scmutil.filtervfs(vfs, encodedir)
         self.opener = self.vfs
@@ -342,9 +342,9 b' class basicstore(object):'
 
 class encodedstore(basicstore):
     def __init__(self, path, vfstype):
-        self.path = path + '/store'
+        vfs = vfstype(path + '/store')
+        self.path = vfs.base
         self.createmode = _calcmode(self.path)
-        vfs = vfstype(self.path)
         vfs.createmode = self.createmode
         self.vfs = scmutil.filtervfs(vfs, encodefilename)
         self.opener = self.vfs
@@ -448,10 +448,10 b' class fncachestore(basicstore):'
         else:
             encode = _plainhybridencode
         self.encode = encode
-        self.path = path + '/store'
+        vfs = vfstype(path + '/store')
+        self.path = vfs.base
         self.pathsep = self.path + '/'
         self.createmode = _calcmode(self.path)
-        vfs = vfstype(self.path)
         vfs.createmode = self.createmode
         fnc = fncache(vfs)
         self.fncache = fnc