fingering problem with Note_heads_engraver

[Jim Tisdall]

I've come across the following problem using
Note_heads_engraver (and the Completion_rests_engraver)
on a guitar score that includes fingering.

The following score rewrites notes that span a quarter-note
beat as two notes with a tie.  That's what I want ...

but it also duplicates the fingering on the new, second,
tied note ... which is not desirable.

\version "2.16.2"     % also with latest development version
\header {
  piece = "demonstrate fingering problem with Note_heads_engraver"
}

\score {
        \new Staff {
                \time 3/4
                \key c \major
                \clef "treble_8"
                \new Voice \with {
                        \remove "Note_heads_engraver"
                        \consists "Completion_heads_engraver" completionUnit = 
#(ly:make-moment 1/4)
%                       \remove "Rest_engraver"
%                       \consists "Completion_rest_engraver" completionUnit = 
#(ly:make-moment 1/4)
                }
                {
                        % fingers are represented by e.g. -3 for the 3rd finger
                        % strings are represented by e.g. \5 for the 5th string 
(in a circle)

                        % the following line duplicates string and finger
                        <g,\6-3>8 <c\5-4>4 <e\4-2>4.

                        % the following line duplicates string only (not finger)
                        g,8\6-3 c4\5-4 e4.\4-2
                }
      }
  \layout {
  }
}