Code cleanup phase 2

ota.py

@@ -198,18 +198,19 @@ def _fetch_manifest():
     )
     try:
         r = urequests.get(url, headers=_headers())
-        if r.status_code == 200:
-            data = r.json()
-            r.close()
-            if data.get("content"):
-                import ubinascii
+        try:
+            if r.status_code == 200:
+                data = r.json()
+                if data.get("content"):
+                    import ubinascii
 
-                content = ubinascii.a2b_base64(data["content"]).decode()
-                patterns = [line.strip() for line in content.splitlines()]
-                return [p for p in patterns if p and not p.startswith("#")]
-        else:
-            warn(f"Manifest not found at {OTA_MANIFEST}")
-        r.close()
+                    content = ubinascii.a2b_base64(data["content"]).decode()
+                    patterns = [line.strip() for line in content.splitlines()]
+                    return [p for p in patterns if p and not p.startswith("#")]
+            else:
+                warn(f"Manifest not found at {OTA_MANIFEST}")
+        finally:
+            r.close()
     except Exception as e:
         log_err(f"Failed to fetch manifest: {e}")
     return None