Streamlining of cookie handling in ext/session and setcookie

Up until now the session cookie used "HttpOnly" to indicate cookies
only available through HTTP while setcookie() used "httponly".  The
relevant RFC 6265 claims that case does not matter for this token,
but only explicitely mentions "HttpOnly".  Thus this seems like a
logical choice when streamlining the code.

Also the setcookie implementation now uses the same string constants
as the session extension for other tokens like Max-Age or the domain
attribute.

This change poses a slight risk of backwards incompatibility in places
where people deliberately ignore chapter 5.2.5 of RFC 6265 and perform
case-sensitive checks for the HttpOnly attribute.
Remove usage of pointless COOKIE_SET_COOKIE constant.
5.5.15 now
Fix potential segfault in dns_get_record()

If the remote sends us a packet with a malformed TXT record,
we could end up trying to over-consume the packet and wander
off into overruns.
Merge branch 'PHP-5.4' into PHP-5.5

* PHP-5.4:
  Fix potential segfault in dns_get_record()
Merge branch 'PHP-5.5' into PHP-5.6

* PHP-5.5:
  Fix potential segfault in dns_get_record()
Merge branch 'PHP-5.6'

* PHP-5.6:
  Fix potential segfault in dns_get_record()
Merge branch 'master' of git://github.com/php/php-src
NEWS entry for Fix potential segfault in dns_get_record(
NEWS entry for "Fix potential segfault in dns_get_record()"
NEWS entry for Fix potential segfault in dns_get_record()
Merge branch 'PHP-5.4' into PHP-5.5

* PHP-5.4:
  NEWS entry for "Fix potential segfault in dns_get_record()"
Merge branch 'PHP-5.5' into PHP-5.6

* PHP-5.5:
  NEWS entry for "Fix potential segfault in dns_get_record()"
  NEWS entry for Fix potential segfault in dns_get_record(
  5.5.15 now

Conflicts:
	configure.in
	main/php_version.h
Merge branch 'PHP-5.6'

* PHP-5.6:
  NEWS entry for Fix potential segfault in dns_get_record()
  NEWS entry for "Fix potential segfault in dns_get_record()"
  NEWS entry for Fix potential segfault in dns_get_record(
  5.5.15 now
Merge branch 'httponly-cookies' of https://github.com/mj/php-src
Merge branch 'master' of git://github.com/php/php-src