sshutils: fix bug in ls() and glob1()

Updated these functions to use posixpath everywhere internally given
that they operate on remote (posix) paths. This was originally the plan
but clearly my mind drifted off while implementing...:/

closes gh-147

starcluster/sshutils/__init__.py

@@ -328,7 +328,7 @@ def ls(self, path):
         """
         Return a list containing the names of the entries in the remote path.
         """
-        return [os.path.join(path, f) for f in self.sftp.listdir(path)]
+        return [posixpath.join(path, f) for f in self.sftp.listdir(path)]
 
     def glob(self, pattern):
         return self._glob.glob(pattern)
@@ -738,7 +738,7 @@ def glob1(self, dirname, pattern):
             #dirname = unicode(dirname, encoding)
             dirname = unicode(dirname, 'UTF-8')
         try:
-            names = [os.path.basename(n) for n in self.paramiko.ls(dirname)]
+            names = [posixpath.basename(n) for n in self.paramiko.ls(dirname)]
         except os.error:
             return []
         if pattern[0] != '.':