Change appearance of clef octavation (issue 3295) (issue 8359043)

[tdanielsmusic]

Like Phil and his wife, I prefer the current version.
This patch makes the octavation symbol too coarse
and heavy.  I suspect the old scores which used
punches to engrave the octavation symbol were
not able to reliably reproduce small light italic
characters and had no option but to use a heavy
typeface.  Modern scores seem to prefer a lighter
touch.

https://codereview.appspot.com/8359043/