Refactor: tools: Use g_set_error throughout crm_node.

This is in preparation for converting to formatted output. Basically,
everywhere we were calling fprintf for an error message and their
returning should be a call to g_set_error. There are a couple other
things going on here:

• I skipped the spot where we're printing out command line usage. This will get handled by formatted output code.

• I removed a call to crm_err in a command line callback that seems redundant, as well as replaced a call elsewhere. This means these won't be logged, but I'm not sure it's terribly important.

• There were several spots in controller_event_cb where we returned an error message but didn't set any particular error code. I've changed these to set exit_code to CRM_EX_PROTOCOL.