[LyX/master] Avoid implicit copy

[Georg Baum]

commit 208e67c7a75d6584d1ebb278b9e6322e7db4a024
Author: Georg Baum <b...@lyx.org>
Date:   Sun Nov 30 12:59:00 2014 +0100

    Avoid implicit copy

diff --git a/src/mathed/InsetMathFont.cpp b/src/mathed/InsetMathFont.cpp
index b499858..18af75d 100644
--- a/src/mathed/InsetMathFont.cpp
+++ b/src/mathed/InsetMathFont.cpp
@@ -66,7 +66,7 @@ void InsetMathFont::metrics(MetricsInfo & mi, Dimension & 
dim) const
 
 void InsetMathFont::draw(PainterInfo & pi, int x, int y) const
 {
-       FontSetChanger dummy(pi.base, key_->name.c_str());
+       FontSetChanger dummy(pi.base, key_->name);
        cell(0).draw(pi, x + 1, y);
        drawMarkers(pi, x, y);
        setPosCache(pi, x, y);