Fix #32541 - Some artic. anchor not saved in style dlg

If some values are used for articulation anchors in the "Style | General" dlg box, they are not restored when opening the dlg again and presumably lost.

See http://musescore.org/en/node/32541 for details.
Merge pull request #1284 from mgavioli/Fix_32541_articulation_anchor_not_saved

Fix #32541 - Some artic. anchor not saved in style dlg