requirements: Rename py3_prod.txt to prod.txt.

requirements/README.md

@@ -1,7 +1,7 @@
 The dependency graph of the requirements is as follows:
 
 ```
-dev           py3_prod
+dev             prod
 + +              +
 | +->py3_common<-+
 |     |
@@ -11,7 +11,7 @@ v
 mypy,docs,py3k
 ```
 
-Of the files, only dev, py3_prod, and mypy have been used in the install
+Of the files, only dev, prod, and mypy have been used in the install
 scripts directly. The rest are implicit dependencies.
 
 py3_common and dev locked.

scripts/lib/create-production-venv

@@ -28,7 +28,7 @@ os.chdir(ZULIP_PATH)
 venv_name = "zulip-venv" if sys.version_info[0] == 2 else "zulip-py3-venv"
 cached_venv_path = setup_virtualenv(
     os.path.join(args.deploy_path, venv_name),
-    os.path.join(ZULIP_PATH, "requirements", "py{}_prod.txt".format(python_version)),
+    os.path.join(ZULIP_PATH, "requirements", "prod.txt"),
     virtualenv_args=['-p', 'python{}'.format(python_version)])
 
 current_venv_path = os.path.join(args.deploy_path, 'zulip-current-venv')