Check for empty basename in GetFileContentOrDie() (#1558)
Check for empty basename in GetFileContentOrDie() (#1558)

An empty basename would mean a directory path is returned by
GetFullPathOrDie(), which then leads to a cryptic exception when trying
to read from it using the istreambuf_iterator:

"basic_filebuf::underflow error reading the file: iostream error"
googlecartographer/cartographer,larics/cartographer,googlecartographer/cartographer,wohe/cartographer,cartographer-project/cartographer,cartographer-project/cartographer,larics/cartographer,wohe/cartographer,cartographer-project/cartographer,wohe/cartographer,larics/cartographer,cartographer-project/cartographer,googlecartographer/cartographer,larics/cartographer,wohe/cartographer,googlecartographer/cartographer