Issue 2745: clef change confuses manual key signature (issue 6450128)

[k-ohara5a5a]

http://codereview.appspot.com/6450128/diff/1/scm/music-functions.scm
File scm/music-functions.scm (right):

http://codereview.appspot.com/6450128/diff/1/scm/music-functions.scm#newcode1608
scm/music-functions.scm:1608: (cons (car entry) (cons 'clef (cddr
entry))))))
We can also get entries of the form
 (octave . notename) . alter)
leaking into localKeySignature and causing trouble here.

{ \set Staff.keySignature = #`(((0 . 4) . ,SHARP) ((0 . 3) . ,SHARP))
  fis'1   \key d\major \clef bass   R1 }

http://codereview.appspot.com/6450128/