QUIC: fixed split frames error handling. Do not corrupt frame data chain pointer on ngx_quic_read_buffer() error. The error leads to closing a QUIC connection where the frame may be used as part of the QUIC connection tear down, which envolves writing pending frames, including this one.

make -f misc/GNUmakefile release

the required tools:
*) xsltproc to build CHANGES,
*) xslscript.pl ( http://hg.nginx.org/xslscript ) to build XSLTs
   from XSLScript sources.


make -f misc/GNUmakefile icons

the required tool:
*) netpbm to create Win32 icons from xpm sources.