e2scrub,e2scrub_all: print a (more understandable) error if not run as root

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/scrub/e2scrub.in b/scrub/e2scrub.in
index 3015749..666d648 100644
--- a/scrub/e2scrub.in
+++ b/scrub/e2scrub.in
@@ -25,6 +25,11 @@
 
 PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
 
+if (( $EUID != 0 )); then
+    echo "e2scrub must be run as root"
+    exit 1
+fi
+
 snap_size_mb=256
 fstrim=0
 reap=0
diff --git a/scrub/e2scrub_all.in b/scrub/e2scrub_all.in
index a53acba..31ebc79 100644
--- a/scrub/e2scrub_all.in
+++ b/scrub/e2scrub_all.in
@@ -20,6 +20,11 @@
 
 PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
 
+if (( $EUID != 0 )); then
+    echo "e2scrub_all must be run as root"
+    exit 1
+fi
+
 scrub_all=0
 snap_size_mb=256
 reap=0