[BUG] libyang data is not freed from after config load if runnings ds is empty.

[Ali-aqrabawi]

to reproduce:

• delete everything from sysrepo running ds.
• run iproute2-sysrepo

sr_subscribe_operational_pull: Successfully subscribed to module (iproute2-ip-rule) operational data pull requests
sr_subscribe_operational_pull: Successfully subscribed to module (iproute2-ip-neighbor) operational data pull requests
sr_subscribe_operational_pull: Successfully subscribed to module (iproute2-tc-qdisc) operational data pull requests
sr_subscribe_operational_pull: Successfully subscribed to module (iproute2-tc-filter) operational data pull requests
^C
Sigint called, exiting...
libyang[1]: String "erspan0" not freed from the dictionary, refcount 8
libyang[1]: String "virbr0" not freed from the dictionary, refcount 12
libyang[1]: String "1" not freed from the dictionary, refcount 6
libyang[1]: String "lo" not freed from the dictionary, refcount 8
libyang[1]: String "red" not freed from the dictionary, refcount 4
libyang[1]: String "pqp" not freed from the dictionary, refcount 8
libyang[1]: String "veth10" not freed from the dictionary, refcount 8
libyang[1]: String "veth20" not freed from the dictionary, refcount 8
libyang[1]: String "uu" not freed from the dictionary, refcount 8
libyang[1]: String "gns3tap1-0" not freed from the dictionary, refcount 8
libyang[1]: String "wlp7s0" not freed from the dictionary, refcount 8
libyang[1]: String "gns3tap2-0" not freed from the dictionary, refcount 8
libyang[1]: String "docker0" not freed from the dictionary, refcount 12
libyang[1]: String "enp8s0" not freed from the dictionary, refcount 8
libyang[1]: String "gretap0" not freed from the dictionary, refcount 8
libyang[1]: String "gns3tap0-0" not freed from the dictionary, refcount 8
libyang[1]: String "iii" not freed from the dictionary, refcount 8