vagrant: use pyinstaller v3.3.1

the fix that i made in v3.3-fixed is also in official release v3.3.1.

Vagrantfile

@@ -143,7 +143,7 @@ def install_pyinstaller()
     . borg-env/bin/activate
     git clone https://github.com/thomaswaldmann/pyinstaller.git
     cd pyinstaller
-    git checkout v3.3-fixed
+    git checkout v3.3.1
     python setup.py install
   EOF
 end