Merge pull request #372 from tmm1/linux-proc-mounts

Read disk partitions on linux from /proc/mounts instead of /etc/mtab
diff --git a/disk/disk_linux.go b/disk/disk_linux.go
index 5595b76..63aa23b 100644
--- a/disk/disk_linux.go
+++ b/disk/disk_linux.go
@@ -214,10 +214,8 @@
 // Partitions returns disk partitions. If all is false, returns
 // physical devices only (e.g. hard disks, cd-rom drives, USB keys)
 // and ignore all others (e.g. memory partitions such as /dev/shm)
-//
-// should use setmntent(3) but this implement use /etc/mtab file
 func Partitions(all bool) ([]PartitionStat, error) {
-	filename := common.HostEtc("mtab")
+	filename := common.HostProc("self/mounts")
 	lines, err := common.ReadLines(filename)
 	if err != nil {
 		return nil, err