Make use of va_args more appropriate to form in various res_config modules plus utils.

Make use of va_args more appropriate to form in various res_config modules plus utils.

A number of va_copy operations weren't matched with a corresponding va_end in res_config_odbc. Also, there was a potential for va_end to be invoked twice on the same va_arg in utils, which would mean invoking va_end on an undefined variable... which is bad.
va_end is removed from various functions in config_pgsql and config_curl since they aren't making their own copy.  The invokers of those functions are responsible for calling va_end on them.

(issue ASTERISK-19451)
Reported by: Walter Doekes
Review: https://reviewboard.asterisk.org/r/1848/

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@362354 65c4cc65-6c06-0410-ace0-fbb531ad65f3