src/libqrtr-lib/meson.build: fix static build

Replace shared_library by library to avoid the following static build failure:

[5/5] Linking target src/libqrtr-glib/libqrtr-glib.so.0.0.0
FAILED: src/libqrtr-glib/libqrtr-glib.so.0.0.0

Fixes:

• http://autobuild.buildroot.org/results/e0442e97279a07f33a14ec52840f98b7ec0fe32d

Signed-off-by: Fabrice Fontaine fontaine.fabrice@gmail.com