[mod_webdav] fix startup crash w/ multiple conds (fixes #2958)
[mod_webdav] fix startup crash w/ multiple conds (fixes #2958)

(thx flynn)

x-ref:
  "lighttpd 1.4.54 segfaults on start in mod_webdav"
  https://redmine.lighttpd.net/issues/2958

gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,lighttpd/lighttpd1.4,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,gstrauss/lighttpd1.4