Fix the coding style in a few files.

Fixes: db1228b3 ("Avoid hardcoded string length")
Fixes: 71fc9c04 ("Avoid risk of "too far memory read"")
Fixes: 2341916a ("Avoid double lxc-freeze/unfreeze")
Fixes: 9eb9ce3e ("Update freezer.c")
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>