- m_main: if --log-file-qualifier applies, do not add ".pid"
at the end of the name
- Fix the logic which detected whether the just-devised name
already existed. This was broken (by me) because it could not
distinguish the reasons for failing to open the logfile.
Doing this required changing the return type of VG_(open)
from Int to SysRes (to make failure reasons visible) and
that's the cause of most of the changes.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@4228
