[mod_cgi] permit CGI exec of unreadable files (fixes #2374)
[mod_cgi] permit CGI exec of unreadable files (fixes #2374)

CGI target might be executable (+x), but not readable (-r)

x-ref:
  "lighttpd-1.4.29 cannot execute unreadable CGIs"
  https://redmine.lighttpd.net/issues/2374

gstrauss/lighttpd1.4,gstrauss/lighttpd1.4,PatchyFog/lighttpd1.4-mbedtls,PatchyFog/lighttpd1.4-mbedtls,gstrauss/lighttpd1.4,gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,PatchyFog/lighttpd1.4-mbedtls,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,lighttpd/lighttpd1.4,PatchyFog/lighttpd1.4-mbedtls,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,PatchyFog/lighttpd1.4-mbedtls,lighttpd/lighttpd1.4,PatchyFog/lighttpd1.4-mbedtls,PatchyFog/lighttpd1.4-mbedtls