git-p4: add raw option to read_pipelines

Previously the read_lines function always decoded the result lines. In
order to improve support for non-decoded binary processing of data in
git-p4.py, this patch adds a raw option to the function that allows
decoding to be disabled.

Signed-off-by: Joel Holdsworth <jholdsworth@nvidia.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-p4.py

@@ -340,17 +340,19 @@ def p4_read_pipe(c, ignore_error=False, raw=False):
     real_cmd = p4_build_cmd(c)
     return read_pipe(real_cmd, ignore_error, raw=raw)
 
-def read_pipe_lines(c):
+def read_pipe_lines(c, raw=False):
     if verbose:
         sys.stderr.write('Reading pipe: %s\n' % str(c))
 
     expand = not isinstance(c, list)
     p = subprocess.Popen(c, stdout=subprocess.PIPE, shell=expand)
     pipe = p.stdout
-    val = [decode_text_stream(line) for line in pipe.readlines()]
+    lines = pipe.readlines()
+    if not raw:
+        lines = [decode_text_stream(line) for line in lines]
     if pipe.close() or p.wait():
         die('Command failed: %s' % str(c))
-    return val
+    return lines
 
 def p4_read_pipe_lines(c):
     """Specifically invoke p4 on the command supplied. """