Fix home directory and env expansion in volume paths

Signed-off-by: Aanand Prasad <aanand.prasad@gmail.com>

compose/config.py

@@ -328,6 +328,8 @@ def resolve_host_paths(volumes, working_dir=None):
 def resolve_host_path(volume, working_dir):
     container_path, host_path = split_volume(volume)
     if host_path is not None:
+        host_path = os.path.expanduser(host_path)
+        host_path = os.path.expandvars(host_path)
         return "%s:%s" % (expand_path(working_dir, host_path), container_path)
     else:
         return container_path

compose/service.py

@@ -3,7 +3,6 @@ from __future__ import absolute_import
 from collections import namedtuple
 import logging
 import re
-import os
 from operator import attrgetter
 import sys
 import six
@@ -586,8 +585,7 @@ def parse_repository_tag(s):
 
 def build_volume_binding(volume_spec):
     internal = {'bind': volume_spec.internal, 'ro': volume_spec.mode == 'ro'}
-    external = os.path.expanduser(volume_spec.external)
-    return os.path.abspath(os.path.expandvars(external)), internal
+    return volume_spec.external, internal
 
 
 def build_port_bindings(ports):