gclient runhooks: now with less spammy progress notifications

Bug: 772741
Change-Id: I62ad64219ba27ee4ea26ceb603b1133dff4a2e04
Reviewed-on: https://chromium-review.googlesource.com/727194
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Daniel Cheng <dcheng@chromium.org>
diff --git a/gclient_utils.py b/gclient_utils.py
index 90f577b..23b9dd7 100644
--- a/gclient_utils.py
+++ b/gclient_utils.py
@@ -291,7 +291,11 @@
   """
   stdout = kwargs.setdefault('stdout', sys.stdout)
   if header is None:
-    header = "________ running '%s' in '%s'\n" % (
+    # The automatically generated header only prepends newline if always is
+    # false: always is usually set to false if there's an external progress
+    # display, and it's better not to clobber it in that case.
+    header = "%s________ running '%s' in '%s'\n" % (
+                 '' if always else '\n',
                  ' '.join(args), kwargs.get('cwd', '.'))
 
   if always: