Add _() to fix i18N compliance (part 2)

In heat, almost 200 log message and at least 30 exception
message are not processed by _(), and will not been translated.
We should use '_("STRING ...")' to enable i18n support.

I split to two parts for review easier because the files
lost of _() are too much.

Change-Id: I36ccd119fc1dcb58e98b77b2c9d139af6a380a7a
Closes-Bug: #1249217
Merge "Add _() to fix i18N compliance (part 2)"