workaround for raw_input() on Windows

workaround for raw_input() on Windows

Since change a3fe91b4f6eb, Mercurial has set_binary() on stdin, stdout, and stderr.
On Windows, this had the side effect of causing raw_input() to emit trailing carriage
returns on it's returned strings.  This was causing web authentication problems.

--- a/mercurial/ui.py	Tue Dec 04 23:28:10 2007 +0100
+++ b/mercurial/ui.py	Mon Dec 03 17:28:26 2007 -0600
@@ -403,7 +403,12 @@
                 readline.read_history_file
             except ImportError:
                 pass
-        return raw_input(prompt)
+        line = raw_input(prompt)
+        # When stdin is in binary mode on Windows, it can cause
+        # raw_input() to emit an extra trailing carriage return
+        if os.linesep == '\r\n' and line and line[-1] == '\r':
+            line = line[:-1]
+        return line
 
     def prompt(self, msg, pat=None, default="y", matchflags=0):
         if not self.interactive: return default