do not discard new manual-bits while applying EDSP solutions

do not discard new manual-bits while applying EDSP solutions

In private-install.cc we call MarkInstall with FromUser=true, which sets
the bit accordingly, but while applying the EDSP solution we call mark
install on all packages with FromUser=false, so MarkInstall believes
this install is an automatic one and sets it to auto – so that a new package
which is explicitely installed via an external solver is marked as auto
and is hence also up for garbage collection in a following call.

Ideally MarkInstall wouldn't reset it, but the detection is hard to do
without regressing in other cases – and ideally ideally MarkInstall
wouldn't deal with the autobit at all – so we work around this on the
calling side for now.