tools/libxenstat: fix populating vbd.rd_sect

Fixes: 91c3e3dc91 ("tools/xentop: Display '-' when stats are not available.")
Signed-off-by: Richard Kojedzinszky <richard@kojedz.in>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
(cherry picked from commit 89d57f291e)

tools/xenstat/libxenstat/src/xenstat_linux.c

@@ -474,7 +474,7 @@ int xenstat_collect_vbds(xenstat_node * node)
 				(read_attributes_vbd(dp->d_name, "statistics/wr_req", buf, 256)<=0) ||
 				((ret = sscanf(buf, "%llu", &vbd.wr_reqs)) != 1) ||
 				(read_attributes_vbd(dp->d_name, "statistics/rd_sect", buf, 256)<=0) ||
-				((ret = sscanf(buf, "%llu", &vbd.wr_sects)) != 1) ||
+				((ret = sscanf(buf, "%llu", &vbd.rd_sects)) != 1) ||
 				(read_attributes_vbd(dp->d_name, "statistics/wr_sect", buf, 256)<=0) ||
 				((ret = sscanf(buf, "%llu", &vbd.wr_sects)) != 1))
 			{