xenFormatXLDisk: Don't leak @target

==11260== 1,006 bytes in 1 blocks are definitely lost in loss record 106 of 111
==11260==    at 0x4C2AE5F: malloc (vg_replace_malloc.c:297)
==11260==    by 0x4C2BDFF: realloc (vg_replace_malloc.c:693)
==11260==    by 0x4EA430B: virReallocN (viralloc.c:245)
==11260==    by 0x4EA7C52: virBufferGrow (virbuffer.c:130)
==11260==    by 0x4EA7D28: virBufferAdd (virbuffer.c:165)
==11260==    by 0x4EA8E10: virBufferStrcat (virbuffer.c:718)
==11260==    by 0x42D263: xenFormatXLDiskSrcNet (xen_xl.c:960)
==11260==    by 0x42D4EB: xenFormatXLDiskSrc (xen_xl.c:1015)
==11260==    by 0x42D870: xenFormatXLDisk (xen_xl.c:1101)
==11260==    by 0x42DA89: xenFormatXLDomainDisks (xen_xl.c:1148)
==11260==    by 0x42EAF8: xenFormatXL (xen_xl.c:1558)
==11260==    by 0x40E85F: testCompareParseXML (xlconfigtest.c:105)
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

src/xenconfig/xen_xl.c

@@ -1034,6 +1034,7 @@ xenFormatXLDisk(virConfValuePtr list, virDomainDiskDefPtr disk)
     int format = virDomainDiskGetFormat(disk);
     const char *driver = virDomainDiskGetDriver(disk);
     char *target = NULL;
+    int ret = -1;
 
     /* format */
     virBufferAddLit(&buf, "format=");
@@ -1119,12 +1120,12 @@ xenFormatXLDisk(virConfValuePtr list, virDomainDiskDefPtr disk)
         tmp->next = val;
     else
         list->list = val;
-    return 0;
+    ret = 0;
 
  cleanup:
     VIR_FREE(target);
     virBufferFreeAndReset(&buf);
-    return -1;
+    return ret;
 }