when the QFile object is already constructed, querying whether the file
exists is actually cheap, so do it right away instead of later on
demand. that makes the calling code a bit cleaner.
fwiw, that we need to explicitly query the file's existence at all is a
result of QFile's completely useless error "codes" (which merely say
which function failed, as if the caller would not know).
Change-Id: Ifec39d05b1713d8128046f679287e510f10e45dc
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>
(cherry picked from qtcreator/5ba32e3484ead2e35cc7732dcd59a97e7459dbfd)
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>