Remove mate-tweak helper, old patch now in upstream src

The flidas make-mate-tweak helper was adding a single line...

--unredir-if-possible-exclude "class_g = 'Mate-screensaver'" \

.. to the marco-compton and metacity-compton scripts. The marco-compton line is now included in the upstream code for mate-tweak in bionic, and the metacity-compton script no longer exists.

https://github.com/ubuntu-mate/mate-tweak/blob/8dd9931aa57ed176fef01cf516c8f4cf90cf9d4e/marco-compton#L42

I have installed upstream mate-tweak_18.04.16-1_all.deb and it seems to be working.

helpers/DATA/mate-tweak/screensaver-nounredir.patch

---- a/marco-compton     2016-04-11 09:19:13.000000000 -0400
-+++ b/marco-compton     2017-04-19 23:04:50.406817419 -0400
-@@ -40,6 +40,7 @@
-         --mark-wmwin-focused \
-         -r 10 -o 0.225 -l -12 -t -12 \
-         -c -C -G \
-+        --unredir-if-possible-exclude "class_g = 'Mate-screensaver'" \
-         --shadow-exclude "! name~=''" \
-         --shadow-exclude "name = 'Notification'" \
-         --shadow-exclude "name = 'Plank'" \
---- a/metacity-compton  2016-04-11 09:19:13.000000000 -0400
-+++ b/metacity-compton  2017-04-19 23:04:35.926817421 -0400
-@@ -40,6 +40,7 @@
-         --mark-wmwin-focused \
-         -r 7 -o 0.09 -l -8 -t -8 \
-         -c -C -G \
-+        --unredir-if-possible-exclude "class_g = 'Mate-screensaver'" \
-         --shadow-exclude "! name~=''" \
-         --shadow-exclude "name = 'Notification'" \
-         --shadow-exclude "name = 'Plank'" \