Fixed error message, PyPy3

plugins/python-build/share/python-build/pypy3.5-portable-5.8.0

@@ -5,7 +5,7 @@ case "$(pypy_architecture 2>/dev/null || true)" in
 * )
   { echo
     colorize 1 "ERROR"
-    echo ": Portable PyPy is not available for $(pypy_architecture 2>/dev/null || true)."
+    echo ": Portable PyPy3 is not available for $(pypy_architecture 2>/dev/null || true)."
     echo
   } >&2
   exit 1