One more MSBuild build fix for VS 2012

Don't know why others who have built with VS 2012 don't have this
problem (?), but otherwise I get:

Project "Q:\ooo\git\master\workdir\wntmsci14\UnpackedTarball\cdr\build\win32\libcdr.vcxproj" on node 1 (default targets).
C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\Platforms\Win32\Microsoft.Cpp.Win32.Targets(518,5): error MSB8008: Specified platform toolset (v110) is not installed or invalid. Please make sure that a supported PlatformToolset value is selected. [Q:\ooo\git\master\workdir\wntmsci14\UnpackedTarball\cdr\build\win32\libcdr.vcxproj]
Done Building Project "Q:\ooo\git\master\workdir\wntmsci14\UnpackedTarball\cdr\build\win32\libcdr.vcxproj" (default targets) -- FAILED.

libcdr/ExternalProject_libcdr.mk

@@ -48,7 +48,7 @@ $(call gb_ExternalProject_get_state_target,libcdr,build) :
 	&& export LIBWPG_INCLUDE_DIR=$(OUTDIR)/inc/external \
 	&& export LCMS2_INCLUDE_DIR=$(call gb_UnpackedTarball_get_dir,lcms2/include) \
 	&& export ZLIB_INCLUDE_DIR=$(OUTDIR)/inc/external/zlib \
-	&& msbuild.exe libcdr.vcxproj /p:PlatformToolset=v110 /p:Configuration=Release \
+	&& msbuild.exe libcdr.vcxproj /p:PlatformToolset=v110 /p:VisualStudioVersion=11.0 /p:Configuration=Release \
 	&& touch $@
 endif