[PATCH] Fix SVN 1.7 build issues with VS >2010

Hi,

trying to build SVN >= 1.7.21 using VS 2015 fails with some linker errors.
As far as I could find out this is due neon being built with an
incorrect toolset (in my case it was building it with the VS 2010
toolset, while it should actually use the 2015 one).

Traced it down to a missing PlatformToolset-setting in the generated
neon project file.

Attached is a suggested patch for 1.7 to correct that. It's basically
merging the part of r1245152 to the 1.7 branch which was left-out by the
VS2015-backport branch which was integrated in 1.7.21.

[[
Fix linker errors when building 1.7 with Neon (potentially also for Serf and
the locale project) under VS >= 2010 and the default platform toolset
differing
from the targeted one.

* generator/templates/neon.vcxproj.ezt
* generator/templates/serf.vcproj.ezt
* generator/templates/svn_locale.vcxproj.ezt
    Add missing PlatformToolset-node.
]]

Regards,
Stefan