py3: Fix encoding and use sys.stdin.buffer

* exc.py: Encode body in response before calling replace over it.
* http.py: prepend the bytes literal to the empty string or else
  we hit bug 1342080 again in python 3.
* utils.py: Use sys.stdin.buffer in python 3.

Change-Id: Ieefb8c633658e507486438e5518c5d53e819027d

glanceclient/common/utils.py

@@ -360,9 +360,12 @@ def get_data_file(args):
             return None
         if not sys.stdin.isatty():
             # (2) image data is provided through standard input
+            image = sys.stdin
+            if hasattr(sys.stdin, 'buffer'):
+                image = sys.stdin.buffer
             if msvcrt:
-                msvcrt.setmode(sys.stdin.fileno(), os.O_BINARY)
-            return sys.stdin
+                msvcrt.setmode(image.fileno(), os.O_BINARY)
+            return image
         else:
             # (3) no image data provided
             return None