Print drone version/revision first thing at startup

Currently these are printed at the end of init when we start waiting for
client connections - this was done so that this info doesn't get lost in
the barrage of init logs. The downside is if there is a crash during
init, we don't get to know the version/revision from the logs. With this
change this info is printed twice - first thing when we start and just
after init when we start waiting for client connections

server/drone_main.cpp

@@ -49,6 +49,9 @@ int main(int argc, char *argv[])
     int exitCode = 0;
     QCoreApplication app(argc, argv);
 
+    qDebug("Version: %s", version);
+    qDebug("Revision: %s", revision);
+
     // TODO: command line options
     // -v (--version)
     // -h (--help)