pylib: remove useless MySQLdb import from sql.py
pylib: fix identation problem in sql.py
pylib: fix remove hasSQL variable from sql.py

it was not usefull since things were going to break anyway without
database connection in many other places
pylib: refactoring: move all Rocks exception in rocks.util

rocks.util already contained some exception used in kickstart
so lazily I move exception.py in util.py (it required less
modification)
rocks-db-perms: now it uses rocks.db.database for DB connection
kickstart: remove getGlobalVar and use getHostAttr instead

This commit replaces getGlobalVar into rocks.db.helper.getHostAttr
tests: simple test for kickstart.cgi