[analog-clock] Render hand also smooth during animation

Summary:
Due to a bug SvgItem had effectively ignoring the value of the smooth
property and acted as if it was "true".
With the bug now fixed, the "false" value as set during hand animation
now is effective again. As result for sensitive eyes this results in
visual glitches, while nobody before ever complained about performance
issues (also does Qt API claim that "In Qt Quick 2.0, this property has
minimal impact on performance.". i.e. linear interpolation vs nearest
neighbor filters as also done in the SvgItem implementation has not
a big effect).

Reviewers: #plasma, davidedmundson

Reviewed By: #plasma, davidedmundson

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D20561