patman: Convert camel case in command.py

Convert this file to snake case and update all files which use it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/buildman/control.py b/tools/buildman/control.py
index e8a531e..ebab126 100644
--- a/tools/buildman/control.py
+++ b/tools/buildman/control.py
@@ -307,7 +307,7 @@
     if not options.step:
         options.step = len(series.commits) - 1
 
-    gnu_make = command.Output(os.path.join(options.git,
+    gnu_make = command.output(os.path.join(options.git,
             'scripts/show-gnu-make'), raise_on_error=False).rstrip()
     if not gnu_make:
         sys.exit('GNU Make not found')