[core] fix include_shell on inline shell commands (fixes #2910)
[core] fix include_shell on inline shell commands (fixes #2910)

regression in lighttpd 1.4.50

x-ref:
  "include_shell behavior change in 1.4.50"
  https://redmine.lighttpd.net/issues/2910

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