report: make sure control charcters are encoded in xUnit report

Control characters (such as backspace, used in progress reports by
mkfs.ext4, for example) can make Python's XML parsers choke, claiming
that it is an invalid XML document.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

common/report

@@ -27,11 +27,12 @@ REPORT_ENV_LIST="$REPORT_ENV_LIST OVL_WORK"
 
 encode_xml()
 {
-    sed -e 's/&/\&/g' \
-	-e 's/>/\>/g' \
-	-e 's/</\&lt;/g' \
-	-e "s/'/\&apos;/g" \
-	-e 's/"/\&quot;/g'
+	cat -v | \
+	    sed -e 's/&/\&amp;/g' \
+		-e 's/>/\&gt;/g' \
+		-e 's/</\&lt;/g' \
+		-e "s/'/\&apos;/g" \
+		-e 's/"/\&quot;/g'
 }
 
 #