storage: Fix a problem which will cause libvirtd crashed
storage: Fix a problem which will cause libvirtd crashed

If pool xml has no definition for "port", then "Segmentation fault"
happens when jumping to "cleanup:" to do "VIR_FREE(port)", as "port"
was not initialized in this situation.

* src/conf/storage_conf.c
(cherry picked from commit 98a4e5a301eb96b4d6c80b859e9986491e1eae06)

Signed-off-by: Steve Hodgson <eb20a6615749cf04ff61aa37e18f749ed6d01446@solarflare.com>

sshah-solarflare/Libvirt-PCI-passthrough-,sshah-solarflare/Libvirt-PCI-passthrough-,sshah-solarflare/Libvirt-PCI-passthrough-,sshah-solarflare/Libvirt-PCI-passthrough-,sshah-solarflare/Libvirt-PCI-passthrough-