Bug#949357: casacore-data-observatories build depends on the removed

[Adrian Bunk]

Source: casacore-data-observatories
Version: 0+git2018.12.08-1
Severity: serious
Tags: ftbfs bullseye sid

libcasa-meas3 is no longer built by src:casacore.

It also looks wrong and unnecessary, and python3-casacore already
depends on libcasa-meas.