Change leftover %-logging calls to lazy

Change-Id: I0bee8d02ac364ab93f77919cae78afa386b85c85
Reviewed-on: https://forge.frm2.tum.de/review/c/secop/frappy/+/30899
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Alexander Zaft <a.zaft@fz-juelich.de>

frappy_mlz/amagnet.py

@@ -162,7 +162,7 @@ class GarfieldMagnet(SequencerMixin, Drivable):
             minslope = min(entry[0]
                            for entry in self.calibrationtable.values())
             self.log.error(
-                'unconfigured calibration for symmetry %r' %
+                'unconfigured calibration for symmetry %r',
                 self._symmetry.value)
             return [minslope, 0, 0, 0, 0]