NetworkPkg:Fix a bug the 2nd httpboot fail issue.

NetworkPkg:Fix a bug the 2nd httpboot fail issue.

Httpboot over Ipv4 or Ipv6 stack,for both Identity and chunked transfer
mode,when the last data has been parsed by HttpLib, the
HttpInstance->NextMsg pointer should point a correct location.Now after
the first successful httpboot for ipv4 or ipv6,the
HttpInstance->NextMsgpoint the character after the last byte, it may
be a bad buffer if we don't receive another HttpHeader, so if call a
2nd httpboot, the wrong NextMsg pointer will cause the httpboot fail,
so we need to check this case in HttpBodyParserCallback function in
the first http boot process.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Zhang Lubo <lubo.zhang@intel.com>
Reviewed-by: Fu Siyuan <siyuan.fu@intel.com>
Reviewed-by: Ye Ting <ting.ye@intel.com>
Reviewed-by: Wu Jiaxin <jiaxin.wu@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19423 6f19259b-4bc3-4df7-8a09-765794883524