xenMakeIPList: Don't leak @address_array

xenMakeIPList: Don't leak @address_array

==32171== 32 bytes in 1 blocks are definitely lost in loss record 44 of 107
==32171==    at 0x4C2DEF6: calloc (vg_replace_malloc.c:711)
==32171==    by 0x55744A9: virAllocN (viralloc.c:191)
==32171==    by 0x12CED2: xenMakeIPList (xen_common.c:1186)
==32171==    by 0x12D0BE: xenFormatNet (xen_common.c:1221)
==32171==    by 0x12F0D2: xenFormatVif (xen_common.c:1889)
==32171==    by 0x12F2B4: xenFormatConfigCommon (xen_common.c:1944)
==32171==    by 0x13BA32: xenFormatXL (xen_xl.c:1971)
==32171==    by 0x1186CA: testCompareParseXML (xlconfigtest.c:105)
==32171==    by 0x118A64: testCompareHelper (xlconfigtest.c:205)
==32171==    by 0x119E36: virTestRun (testutils.c:180)
==32171==    by 0x11970E: mymain (xlconfigtest.c:301)
==32171==    by 0x11BEE3: virTestMain (testutils.c:1119)

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>