Replace SWIG=C:/Program Files/Git/local/bin/swig with just SWIG=swig

Rakefile

@@ -221,7 +221,7 @@ end
 # c:/ruby-1.8.6-p383-preview2/devkit/msys/1.0.11/usr/local/share/swig/1.3.22
 # before running swig on MinGW.
 namespace :swig do
-  SWIG = "/usr/local/bin/swig"
+  SWIG = "swig"
   SWIGFLAGS = "-fcompact -noruntime -c++ -ruby -no_default -I../fox-includes"
   SWIG_LIB = `#{SWIG} -swiglib`.chomp
   SWIG_MODULES = {