Fix message i18n error

Partial-Bug: #1217100

Using tools/check_i18n.py to scan source directory, and fix most of
the errors.

- Message internationalization
- First letter must be capital
- Using comma instead of percent in LOG.xxx

Note: all extension's description are not touched in this patch,
can be fixed after discussing.
Note: all nicira/check_nvp_config.py print messages are not fixed.

Change-Id: I79ef06fd42f6780beb5019c592662536c2a51864
Merge "Fix message i18n error"