refactor: Change variable name for consistent typing (#4823)

`line` gets reused in two different loops in cc_mounts,
causing mypy to think the later line has the same type as the
early line. Change `line` to `entry` to make mypy happy.

cloudinit/config/cc_mounts.py

@@ -573,14 +573,14 @@ def handle(name: str, cfg: Config, cloud: Cloud, args: list) -> None:
     needswap = False
     need_mount_all = False
     dirs = []
-    for line in actlist:
+    for entry in actlist:
         # write 'comment' in the fs_mntops, entry,  claiming this
-        line[3] = "%s,%s" % (line[3], MNT_COMMENT)
-        if line[2] == "swap":
+        entry[3] = "%s,%s" % (entry[3], MNT_COMMENT)
+        if entry[2] == "swap":
             needswap = True
-        if line[1].startswith("/"):
-            dirs.append(line[1])
-        cc_lines.append("\t".join(line))
+        if entry[1].startswith("/"):
+            dirs.append(entry[1])
+        cc_lines.append("\t".join(entry))
 
     mount_points = [
         v["mountpoint"] for k, v in util.mounts().items() if "mountpoint" in v