Revert "scons: Prefer MSVS 2003 (patch by Mark Mueller)."

This reverts commit 19f6e1a975.

SConstruct

@@ -146,13 +146,6 @@ if gcc:
 	env.Append(CXXFLAGS = '-fmessage-length=0')
 
 if msvc:
-	# Force msvc 7.1 (visual studio 2003) for windows builds.
-	# Eventually a way to override this would be nice.
-	# See also http://www.scons.org/wiki/MsvsMultipleVersions
-	env["MSVS"] = {"VERSION": "7.1"}
-	env["MSVS_VERSION"] = "7.1"
-	Tool("msvc")(env)
-	
 	env.Append(CFLAGS = '/W3')
 	if debug:
 		cflags = [