transceiver52M: bump critial errors to ALERT level

Device errors regarding properties such as sample
rate or frequency tuning are almost always fatal and
lead to the common error "assuming TRX is dead".
Make sure that these errors are clearly presented to
the user.

Signed-off-by: Thomas Tsou <ttsou@vt.edu>

git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@2700 19bc5d8c-e614-43d4-8b26-e1612bc8e597

Transceiver52M/runTransceiver.cpp

@@ -80,6 +80,7 @@ int main(int argc, char *argv[])
   int mOversamplingRate = numARFCN/2 + numARFCN;
   RadioDevice *usrp = RadioDevice::make(DEVICERATE);
   if (!usrp->open()) {
+    LOG(ALERT) << "Transceiver exiting..." << std::endl;
     return EXIT_FAILURE;
   }