Removed unnecessary dependency on icinga-core

Closes: #731840
Define icinga-web breaking icinga-idoutils (<< 1.10)

This is a try to stop user to use icinga-web with an old, and incompatible IDO
schema.

Breaks is not actually the best field for this, but the only field that does
block an upgrade.

Closes: #732058
Git-Dch: long
changelog for 1.10.0-2