When SONAME is not set, lintian produces these warnings and error:
W: gammaray: dev-pkg-without-shlib-symlink usr/lib/gammaray_probe.so usr/lib/gammaray_probe.so
W: gammaray: shlib-without-versioned-soname usr/lib/gammaray_probe.so gammaray_probe.so
E: gammaray: postinst-must-call-ldconfig usr/lib/gammaray_probe.so
So the right solution is to override the warnings and add ldconfig call into
postinst script by hand?
Maybe a better solution would be to set the SONAME to the upstream version number.
That way it's explicit that plugins need to be recompiled when the upstream version
changes.