Extensions ignored in YIN format

```
If a module in *YIN format* is loaded via Context::search_module, then all YANG
extensions appearing in it are ignored. It is demonstrated in the attached
example:

1. Go to the "yang" directory first, everything works:

$ pyang test.yang
$ pyang -L hello.xml

2. In the "yin" directory, the first way also works but the other fails:

$ pyang test.yin
$ pyang -L hello.xml
test.yin:7: warning: imported module ietf-yang-metadata not used
test.yin:10: error: no module with the namespace
"urn:ietf:params:xml:ns:yang:ietf-yang-metadata" is imported

It is due to the fact the YinParser in Context::_ensure_revs is
initialised with the "extra" parameter containing 'no_extensions':True
For YangParser, no such parameter is present.
```

Original issue reported on code.google.com by `lada.lho...@gmail.com` on 27 Feb 2015 at 2:29

Attachments:
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