tree: nvme_configure_ctrl(): Set errno to zero on success

Author: tbzatek

src/nvme/tree.c

@@ -1143,6 +1143,7 @@ static int nvme_configure_ctrl(nvme_root_t r, nvme_ctrl_t c, const char *path,
 	c->cntrltype = nvme_get_ctrl_attr(c, "cntrltype");
 	c->dctype = nvme_get_ctrl_attr(c, "dctype");
 
+	errno = 0; /* cleanup after nvme_get_ctrl_attr() */
 	return 0;
 }