databases/cego: update 2.44.6 -> 2.44.7

• In CegoSelect::evalSelection, optimization provided in a way, that schema is not evaluated explizit anymore. Rather the previous analysed schema ( prepare method, _evalSchema ) is used. Since for dynamic field length, the resulting schema must be estiamated, this approach is ok.
• Fix added in CegoFunction::getReturnTypeLen, evalFieldValue for expression values could fail, since FLA ist still not set up. For this case, now the cont value RETVAL_LEN is returned as an estimation.

Submitted by: Bjoern Lemke <lemke@lemke-it.com>