[Clas12_software] Update of DC geometry in CCDB default variation

[Raffaella De Vita]

Dear All,
As discussed at the software meeting today, the DC geometry in the CCDB default variation was updated with the so-called “installation” geometry that accounts for some changes of the chamber positions with respect to the original, pre-installation drawings. The DC geometry in the default variation now coincides with the one in the may_2018_engineers variation, which we have been using routinely for several months. 
This update removes the need of specifying the may_2018_engineers variation in running reconstruction.

As a consequence of this change, gemc 4.2.4 and older version, that used the old DC geometry, are now deprecated. The recommendation for all user is to use gemc 4.3.0, which implements the correct DC geometry. Users who may be interested in reconstructing old simulations Dione with gemc 4.2.4 or older can use the CCDB variation dc_geo_gemc424 that contains the old, pre-installation geometry.

Note that chefs, who are processing real data with DC alignment tables, should continue using the specific variations that were created for this purpose.

Best regards,
		Raffaella