autofs: delete possible duplicate of an autofs entry
Steps to reproduce:
1. Create the following autofs objects
```ldif
dn: ou=auto.master,ou=autofs,dc=ldap,dc=vm
objectClass: automountMap
objectClass: top
ou: auto.master
dn: automountKey=/home,ou=auto.master,ou=autofs,dc=ldap,dc=vm
objectClass: automount
objectClass: top
automountInformation: auto.home
automountKey: /home
dn: ou=auto.home,ou=autofs,dc=ldap,dc=vm
objectClass: automountMap
objectClass: top
ou: auto.home
dn: automountKey=/home1,ou=auto.home,ou=autofs,dc=ldap,dc=vm
objectClass: automount
objectClass: top
automountInformation: home1
automountKey: /home1
```
2. Use e.g. the test tool to fetch the maps:
```
./autofs_test_client auto.master
./autofs_test_client auto.home -n /home1
```
3. Change automountInformation of /home1
```
dn: automountKey=/home1,ou=auto.home,ou=autofs,dc=ldap,dc=vm
objectClass: automount
objectClass: top
automountInformation: home1_1
automountKey: /home1
```
4. Run the test tool again:
```
./autofs_test_client auto.master
./autofs_test_client auto.home -n /home1
> error happens
```
It is important the `get entry by name is called` thus the `-n` parameter.
Resolves:
https://pagure.io/SSSD/sssd/issue/4116
(cherry picked from commit 14b44e721c52207fd17e449cc6ae0a75fbb05369)