makebs: fix config crash

Without this, running makebuildserver from a clean master results in the
following:

	 $ ./makebuildserver
	Traceback (most recent call last):
	  File "./makebuildserver", line 74, in <module>
	    del(config['__builtins__'])  # added by compile/exec
	KeyError: '__builtins__'

This is because a clean checkout has no config, thus exec is never
actually ran.

diff --git a/makebuildserver b/makebuildserver
index 2397fb4b30b132b93a3136297c90fc5c7d19192b..08be3829d45da67618622326efcb85f4227ccb1a 100755 (executable)
--- a/makebuildserver
+++ b/makebuildserver
@@ -71,7 +71,8 @@ if os.path.exists('makebuildserver.config.py'):
 elif os.path.exists('makebs.config.py'):
     # this is the old name for the config file
     exec(compile(open('makebs.config.py').read(), 'makebs.config.py', 'exec'), config)
-del(config['__builtins__'])  # added by compile/exec
+if '__builtins__' in config:
+    del(config['__builtins__'])  # added by compile/exec
 
 if not os.path.exists('makebuildserver') or not os.path.exists(serverdir):
     print('This must be run from the correct directory!')