[FIX] util/misc: split_osenv, do not return [""]

If the env var was not set we returned `[""]`. That was confusing.
It also breaks the boolean check of the result.

With this patch we just return an empty list when the variable is not set.

See also: odoo/upgrade#8174

closes #299

Signed-off-by: Christophe Simonis (chs) <chs@odoo.com>
Co-authored-by: Christophe Simonis (chs) <chs@odoo.com>

Author: aj-fuentes

src/util/misc.py

@@ -189,7 +189,8 @@ def expand_braces(s):
 
 
 def split_osenv(name, default=""):
-    return re.split(r"\W+", os.getenv(name, default).strip())
+    value = os.getenv(name, default).strip()
+    return re.split(r"\W+", value) if value else []
 
 
 try: