Code cleanup: quota limit validation

In the quota limit validation, the conditional expressions are
difficult to understand because -1 which means an unlimited value is
compared directly.

By converting -1 to infinity, the validation can be implemented with
simple numeric comparisons. It makes code maintenance much easier.

Change-Id: I74650cba121734a14d31b76607adea004804c815
Imported Translations from Transifex

For more information about this automatic import see:
https://wiki.openstack.org/wiki/Translations/Infrastructure

Change-Id: I3823ea46b26b921642b373b1495ffb3a448f121f
Merge "Code cleanup: quota limit validation"
Merge "Imported Translations from Transifex"