build/mongodl.py: Fall back to /usr/lib/os-release (#1114)
build/mongodl.py: Fall back to /usr/lib/os-release (#1114)

* build/mongodl.py: Fall back to /usr/lib/os-release

According to `man os-release', file /etc/os-release isn't mandatory
to be present in the system. Fallback to /usr/lib/os-release in
absence of /etc/os-release.

Signed-off-by: Michał Grzelak <fcb7cf1bbaa0f4add37c710d046418bdf0bfb43e@semihalf.com>

* Cleanup os-release lookup

Signed-off-by: Michał Grzelak <fcb7cf1bbaa0f4add37c710d046418bdf0bfb43e@semihalf.com>
Co-authored-by: vector-of-bool <b9d808bd9d22b0365c50952ef6f33a5887a7ef52@gmail.com>
jmikola/mongo-c-driver,jmikola/mongo-c-driver,rcsanchez97/mongo-c-driver,mongodb/mongo-c-driver,mongodb/mongo-c-driver,jmikola/mongo-c-driver,jmikola/mongo-c-driver,mongodb/mongo-c-driver,jmikola/mongo-c-driver,rcsanchez97/mongo-c-driver,jmikola/mongo-c-driver,rcsanchez97/mongo-c-driver,rcsanchez97/mongo-c-driver,rcsanchez97/mongo-c-driver,mongodb/mongo-c-driver,mongodb/mongo-c-driver,mongodb/mongo-c-driver,jmikola/mongo-c-driver,rcsanchez97/mongo-c-driver,rcsanchez97/mongo-c-driver,mongodb/mongo-c-driver