Merge c128116 from 2.13 branch

src/Zope2/Startup/zopectl.py

@@ -180,6 +180,7 @@ class ZopeCtlOptions(ZDOptions):
         self.directory = config.instancehome
         self.clienthome = config.clienthome
         if self.program:
+            if isinstance(self.program, basestring):
                 self.program = [self.program]
         elif config.runner and config.runner.program:
             self.program = config.runner.program