trunk: randomized star/polygon changes shape when moved (rev >= 12554)

A star/polygon with 'Randomized' parameter > 0 changes shape when moved (translated) on canvas.

Steps to reproduce:
1) launch current trunk (default prefs, default new document, locale: en_US)
2) draw a star
3) change parameter 'Randomized:' to e.g. 0.2
4) switch back to select tool
5) move the star (by dragging with the mouse, or with arrow keys)

Expected result:
The star shape is moved to new position, but stays unchanged otherwise.

Actual result:
The star shape is moved to the new position, and the shape gets regenerated (i.e. changes completely).

Based on tests with archived builds on OS X 10.7.5:
- not reproduced with stable 0.48.4, 0.48.5
- not reproduced with 0.48+devel rev <= 12552
- reproduced with 0.48+devel rev >= 12555
this perceived regression was likely introduced with the merge of the GSoC unit-improvement branch in r12554, which changed how transforms for parametrized shapes are optimized (if possibly, transforms get optimized and reflected in the shape parameters instead of stored in a preserved 'transform' attribute):
<http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/changes/12555>

Notes:
- non-uniform scaling, rotating or skewing the randomized star prevents the regression from happening (adds a 'matrix()' transformation)
- uniform scaling, or flipping the object does not prevent the regression

Reproduced with Inkscape 0.48+devel r13466 on OS X 10.7.5.