[SCAD] remove unnecessary Python 3 check

we only support Python 3

src/Mod/OpenSCAD/OpenSCADUtils.py

@@ -106,8 +106,7 @@ def searchforopenscadexe():
         p1 = subprocess.Popen(['which','openscad'], stdout=subprocess.PIPE)
         if p1.wait() == 0:
             output = p1.stdout.read()
-            if sys.version_info.major >= 3:
-                output = output.decode("utf-8")
+            output = output.decode("utf-8")
             opath = output.split('\n')[0]
             return opath