Replace --no-pager with GIT_PAGER=cat

scm.py

Index: scm.py
diff --git a/scm.py b/scm.py
index 8810c2aa2603535eb9937e080c015393acb92ae2..835e0ed5e5d7788314d0688999889a3eab25c18f 100644
--- a/scm.py
+++ b/scm.py
@@ -98,9 +98,12 @@ class GIT(object):
 
   @staticmethod
   def Capture(args, cwd, **kwargs):
+    env = os.environ.copy()
+    # 'cat' is a magical git string that disables pagers on all platforms.
+    env['GIT_PAGER'] = 'cat'
     return subprocess2.check_output(
-        ['git', '--no-pager'] + args,
-        cwd=cwd, stderr=subprocess2.PIPE, **kwargs).strip()
+        ['git'] + args,
+        cwd=cwd, stderr=subprocess2.PIPE, env=env, **kwargs).strip()
 
   @staticmethod
   def CaptureStatus(files, cwd, upstream_branch):