rbutil: Fix bootloader installation for various players.

Reworking handling of player specific data (static player configuration,
as well as information retrieved from the server) changed the behaviour
on a non-present configuration entry. This eventually caused the
mountpoint not being set for players that don't have a bootloader file
on disk. Fixing this accidentially removed the default-if-not-found
handling for the bootloader file.

Restore the old default value behaviour for both cases.

Change-Id: I627782ccdef198619fb507f8b09a64811b3bd18f

utils/rbutilqt/base/bootloaderinstallbase.cpp

@@ -211,6 +211,9 @@ void BootloaderInstallBase::setBlFile(QStringList sl)
             m_blfile = sl.at(a);
         }
     }
+    if(m_blfile.isEmpty() && sl.size() > 0) {
+        m_blfile = sl.at(0);
+    }
 }