fix(config): relocate /run to /var/run on BSD (#4677)

on BSD, /run is not ephemeral.
relocate BSDs config to /var/run

Sponsored by: The FreeBSD Foundation
Fixes GH-4180
Fixes GH-4231
Co-authored-by: Brett Holman <brett.holman@canonical.com>

config/cloud.cfg.tmpl

@@ -326,6 +326,9 @@ system_info:
   paths:
     cloud_dir: /var/lib/cloud/
     templates_dir: /etc/cloud/templates/
+{% elif is_bsd %}
+  paths:
+    run_dir: /var/run/
 {% endif %}
 {% if variant == "debian" %}
   package_mirrors:

tests/unittests/test_ds_identify.py

@@ -339,11 +339,16 @@ def write_mock(data):
         ]
 
         uname = "Linux"
+        runpath = "run"
         written = []
         for d in mocks:
             written.append(d["name"])
             if d["name"] == "uname":
                 uname = d["out"].split(" ")[0]
+        # set runpath so that BSDs use /var/run rather than /run
+        if uname != "Linux":
+            runpath = "var/run"
+
         for data in mocks:
             mocklines.append(write_mock(data))
         for d in default_mocks:
@@ -365,10 +370,6 @@ def write_mock(data):
             out = e.stdout
             err = e.stderr
 
-        runpath = "run"
-        if uname != "Linux":
-            runpath = "var/run"
-
         cfg = None
         cfg_out = os.path.join(rootd, runpath, "cloud-init/cloud.cfg")
         if os.path.exists(cfg_out):