Fix the following clang warning by using NULL instead of '\0'
api.c:6721:17: warning: expression which evaluates to zero treated as a
null pointer constant of type 'char *' [-Wnon-literal-null-conversion]
6721 | mnt_paths[i] = '\0';
| ^~~~
Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com> Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>