Fix issues found by PVS-Studio static analyzer:

mod_mime_magic:
cut'n'paste error rsl_encoding vs. rsl_separator, also simplify code a bit

mod_header:
wrong string initialization (leading to segfault if format argument is missing)

util_win32: duplicate sizeof (untested; Windows people, please review)

PR: 51542
Submitted by: Andrey Karpov <karpov viva64 com>, Stefan Fritsch


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1172732 13f79535-47bb-0310-9956-ffa450edef68