cloudfoundry/cli — pull request #303 by liuhewei (2014-11-19 06:47:46+00:00)
Title: Fix the usage info in cf feature-flag command

when we use 'cf feature-flag' without any feature name, the message is:
```
the usage is
USAGE:
cf feature-flag
```
It's not correct exactly, better to add the required argument as FEATURE_NAME.