apps/netutils/ftpd/ftpd.c: Fixes several problems:

1. This fixes the issue reported in Bitbucket apps/ Issue 15.  That is, if fopen() fails, the NULL stream handle would be used in subsequent logic.  The handling of the failure was incomplete.
2. Some of the error handling was fixed.  In the event of an error, it was return return an error value ONLY if we failure to report the error and even then the wrong error would be reported.  This change now preserves and returns the correct error number that is the root cause of the failure.
3. Ran the file through tools/nxstyle and cleaned up many formatting problems.

Author: gregory-nutt