usertools: print binding errors to stderr
usertools: print binding errors to stderr

Bring consistency to error messages and output them to stderr.
Also, whenever the script tells the user to "check usage", don't
tell the user to do it and just display usage instead.

Signed-off-by: Anatoly Burakov <814e00d8f6e4e81b7ccc7e3e5a0bfec0078f0203@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk