[soldier] ABI: Add libdbus-glib-1.so.2
This library is deprecated, but it's small (around 350K + packaging overhead), and is required by some scout games that bundle a GConf client library (also deprecated) and do not integrate correctly with the scout LD_LIBRARY_PATH runtime.
Resolves: https://github.com/ValveSoftware/steam-runtime/issues/198
Resolves: T29373