fix error reporting for misformed environment variables

slapos/recipe/cmmi/__init__.py

@@ -127,7 +127,7 @@ class Recipe(object):
                     key, value = variable.split('=', 1)
                     self.environ[key.strip()] = value
                 except ValueError:
-                    raise zc.buildout.UserError('Invalid environment variable definition: %s', variable)
+                    raise zc.buildout.UserError('Invalid environment variable definition: %s' % variable)
         # Add prefix to PATH, CPPFLAGS, CFLAGS, CXXFLAGS, LDFLAGS
         if self.buildout_prefix != '':
             self.environ['PATH'] = '%s/bin:%s' % (self.buildout_prefix, self.environ.get('PATH', '/usr/bin'))