Expand Linux distribution detection to /etc/redhat-release and
/etc/debian_version to follow what /usr/bin/lsb_release script does.
If /usr/bin/lsb_release fails to extract the distribution information
from /etc/lsb-release, it then checks /etc/redhat-release and, as a last
fallback, /etc/debian_version.
Some Red Hat distributions have a /etc/lsb-release file that
does not provide the values we are looking for (DISTRIB_ID,
DISTRIB_RELEASE and DISTRIB_DESCRIPTION).
If both productType or productVersion are empty after reading
/etc/lsb-release, readEtcLsbRelease() will return false, allowing
further parsing of /etc/redhat-release. This scenario mimics what
the /usr/bin/lsb_release script does if /etc/lsb-release does not
contains enough information.
The productType and productVersion returned by QSysInfo after reading
/etc/redhat-release match the distributor id and release information
returned by the /usr/bin/lsb_release script.
For Debian Linux distributions where /etc/os-release, /etc/lsb-release
and /etc/redhat-release are not available nor usable, the
/usr/bin/lsb_release script also checks for the /etc/debian_version
file.
In this case, we also enable parsing of /etc/debian_version to retrieve a
fallback productVersion, the productType being set to Debian.
Change-Id: Ia20d513d78be8a8ee8c0410d0aaa052fde81a41d
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
6c20a01cb9