wingrass: update for VC 2015 (merge https://trac.osgeo.org/grass/changeset/68592 from trunk)

git-svn-id: https://svn.osgeo.org/grass/grass/branches/releasebranch_7_0@68594 15284696-431f-4ddb-bdfa-cd5b030d7da7

mswindows/osgeo4w/mklibs.sh

@@ -13,7 +13,7 @@ else
 fi
 
 PROGRAMFILES="/c/Program Files (x86)"
-VSDIR="$PROGRAMFILES/Microsoft Visual Studio 12.0"
+VSDIR="$PROGRAMFILES/Microsoft Visual Studio 14.0"
 PATH="$VSDIR/Common7/IDE:$PATH"
 PATH="$VSDIR/VC/bin:$PATH"
 PATH="$VSDIR/Common7/Tools:$PATH"