[LyX/2.0.x] LaTeXFeatures.cpp: compilation fix for last commit

[Uwe Stöhr]

commit 14fb17d76d93244ceb5a09b8db835d67196e492f
Author: Uwe Stöhr <uwesto...@lyx.org>
Date:   Sat Jul 27 23:06:31 2013 +0200

    LaTeXFeatures.cpp: compilation fix for last commit
    
    (thanks to the latest TortoiseGit update cherry picking and even reverting 
is no longer possible, argh!)

diff --git a/src/LaTeXFeatures.cpp b/src/LaTeXFeatures.cpp
index 48809b2..e642bdc 100644
--- a/src/LaTeXFeatures.cpp
+++ b/src/LaTeXFeatures.cpp
@@ -777,7 +777,7 @@ string const LaTeXFeatures::getPackages() const
        // because esint must be loaded AFTER amslatex and mhchem loads amlatex
        // (this info is from the author of mhchem from June 2013)
        if (mustProvide("mhchem") &&
-           params_.use_package("mhchem") != BufferParams::package_off)
+           params_.use_mhchem != BufferParams::package_off)
                packages << "\\PassOptionsToPackage{version=3}{mhchem}\n"
                            "\\usepackage{mhchem}\n";