Revert "GIT_SILENT: minor qstring optimization"

Authored by mglb on Dec 9 2019, 9:15 PM.

Description

Revert "GIT_SILENT: minor qstring optimization"

This reverts commit f96deb39aacc2e9f22a9b3bda0a2b003f0d85104.

This was anti-optimization.
QStringLiteral is a QString created at build time. Initialization of
QString with it has no overhead.
QLatin1String is 8 bit C string wrapper which needs run-time conversion
to 16 bit encoding used in QString.