provision: Remove the last reference to `install-mypy`, and delete it.

This script has been redundant for some time now.

docs/mypy.md

@@ -79,9 +79,7 @@ coverage is shown in
 
 If you installed Zulip's development environment correctly, mypy
 should already be installed inside the Python 3 virtualenv at
-`zulip-py3-venv` (mypy only supports Python 3).  If it isn't installed
-(e.g. because you haven't reprovisioned recently), you can run
-`tools/install-mypy` to install it.
+`zulip-py3-venv` (mypy only supports Python 3).
 
 ## Running mypy on Zulip's code locally
 

tools/install-mypy

@@ -1,33 +0,0 @@
-#!/bin/bash
-set -e
-
-# This script installs a python3 virtualenv called 'zulip-py3-venv' in zulip's parent directory.
-# It then installs mypy and some other dependencies into that virtualenv.
-# This script has been written for Ubuntu. If you want to install it on some other distro
-# replace these commands with the corresponding commands for your distro.
-# (for e.g. on Fedora replace apt-get with yum or dnf)
-
-TOOLS_DIR=$(dirname "$0")
-PY3_VENV_PATH="/srv/zulip-py3-venv"
-
-if ! which python3 >/dev/null || ! which virtualenv >/dev/null; then
-    if which apt-get; then
-        sudo apt-get install -y python3 python-virtualenv
-    else
-        echo "Please install python3 and python-virtualenv."
-        exit 1
-    fi
-fi
-
-# create venv if required
-if [ -d "$PY3_VENV_PATH" ]; then
-    echo "found virtualenv $PY3_VENV_PATH"
-else
-    echo "creating virtualenv $PY3_VENV_PATH"
-    sudo virtualenv -p python3 "$PY3_VENV_PATH"
-fi
-source "$PY3_VENV_PATH/bin/activate"
-
-# install mypy
-sudo "$PY3_VENV_PATH/bin/pip3" install --upgrade pip
-sudo "$PY3_VENV_PATH/bin/pip3" install --upgrade --no-deps -r "$TOOLS_DIR/../requirements/mypy.txt"