curl: update ssl-multi-backend patch in preparation for v7.55.0
curl: update ssl-multi-backend patch in preparation for v7.55.0

There has been quite a bit of work between cURL v7.54.1 and v7.55.0, and
the patch had to be adjusted accordingly.

Signed-off-by: Johannes Schindelin <53fb8db7833fca1e1746dd8592f61048d350f64c@gmx.de>

dscho/MINGW-packages,dscho/MINGW-packages,dscho/MINGW-packages,git-for-windows/MINGW-packages,git-for-windows/MINGW-packages,dscho/MINGW-packages,git-for-windows/MINGW-packages,dscho/MINGW-packages