misc: fix sed syntax

gen-passwords.sh

@@ -11,7 +11,7 @@ JIGASI_XMPP_PASSWORD=`generatePassword`
 JIBRI_RECORDER_PASSWORD=`generatePassword`
 JIBRI_XMPP_PASSWORD=`generatePassword`
 
-sed -i ".bak" \
+sed -i.bak \
     -e "s#JICOFO_COMPONENT_SECRET=.*#JICOFO_COMPONENT_SECRET=${JICOFO_COMPONENT_SECRET}#g" \
     -e "s#JICOFO_AUTH_PASSWORD=.*#JICOFO_AUTH_PASSWORD=${JICOFO_AUTH_PASSWORD}#g" \
     -e "s#JVB_AUTH_PASSWORD=.*#JVB_AUTH_PASSWORD=${JVB_AUTH_PASSWORD}#g" \