libxl: honor autoballoon setting in libxl.conf

libxlGetAutoballoonConf is supposed to honor user-specified
autoballoon setting in libxl.conf. As written, the user-specified
setting could be overwritten by the subsequent logic to check
dom0_mem parameter. If user-specified setting is present and
correct, accept it. Only fallback to checking Xen dom0_mem
command line parameter if user-specfied setting is not present.
Signed-off-by: NJim Fehlig <jfehlig@suse.com>

src/libxl/libxl_conf.c

@@ -1355,8 +1355,11 @@ libxlGetAutoballoonConf(libxlDriverConfigPtr cfg,
     regex_t regex;
     int res;
 
-    if (virConfGetValueBool(conf, "autoballoon", &cfg->autoballoon) < 0)
+    res = virConfGetValueBool(conf, "autoballoon", &cfg->autoballoon);
+    if (res < 0)
         return -1;
+    else if (res == 1)
+        return 0;
 
     if ((res = regcomp(&regex,
                       "(^| )dom0_mem=((|min:|max:)[0-9]+[bBkKmMgG]?,?)+($| )",