[build] Remove cogl-enum-types.h on distclean
[build] Remove cogl-enum-types.h on distclean

The cogl-enum-types.h file is created by glib-mkenums under
/clutter/cogl/common, and then copied in /clutter/cogl in order
to make the inclusion of that file work inside cogl.h.

Since we're copying it in a different location, the Makefile
for that location has to clean up the copy.

GNOME/clutter,rkudiyarov/clutter_osx,djdeath/clutter,spatulasnout/clutter,Distrotech/clutter,djdeath/clutter,jigpu/clutter,collects/clutter,djdeath/clutter-android,djdeath/clutter-android,spatulasnout/clutter,Distrotech/clutter,djdeath/clutter,nobled/clutter,GNOME/clutter,rkudiyarov/clutter_osx,tardyp/clutter,djdeath/clutter,collects/clutter,Distrotech/clutter,djdeath/clutter-multithreaded,rkudiyarov/clutter_osx,collects/clutter,dlespiau/clutter,ebassi/clutter,ebassi/clutter,collects/clutter,nobled/clutter,heysion/clutter-clone,kerrickstaley/clutter-vala,jigpu/clutter,djdeath/clutter-multithreaded,spatulasnout/clutter,heysion/clutter-clone,djdeath/clutter-android,heysion/clutter-clone,GNOME/clutter,collects/clutter,heysion/clutter-clone,spatulasnout/clutter,djdeath/clutter,dlespiau/clutter,djdeath/clutter-android,jigpu/clutter,Distrotech/clutter,Distrotech/clutter,djdeath/clutter,djdeath/clutter-multithreaded,rkudiyarov/clutter_osx,Distrotech/clutter,jigpu/clutter,nobled/clutter,djdeath/clutter-multithreaded,GNOME/clutter,ebassi/clutter,kerrickstaley/clutter-vala,jigpu/clutter,djdeath/clutter-android,tardyp/clutter,spatulasnout/clutter,ebassi/clutter,kerrickstaley/clutter-vala,tardyp/clutter,dlespiau/clutter,ebassi/clutter,heysion/clutter-clone,jigpu/clutter,GNOME/clutter,kerrickstaley/clutter-vala