functional tests: add missing files to CLEAN_FILES
functional tests: add missing files to CLEAN_FILES

It was making "make clean" fail.

iaguis/rkt,rkt/rkt,sstabellini/rkt,adfernandes/rkt,mike1729/rkt,euank/rkt,jasonchaffee/rkt,blixtra/rkt,tmrts/rkt,jzelinskie/rkt,linki/rkt,jjlakis/rkt,Wilybald/rkt,alban/rkt,jjlakis/rkt,akshaykarle/rkt,intelsdi-x/rkt,dgonyeo/rkt,sinfomicien/rkt,lucasallan/rkt,coreos/rkt,dgonyeo/rkt,yifan-gu/rocket,alban/rkt,mike1729/rkt,coreos/rkt,jjlakis/rkt,kinvolk/rkt,intelsdi-x/rkt,yifan-gu/rkt,Wilybald/rkt,il9ue/rkt,cab105/rkt,markllama/rkt,s-urbaniak/rkt,sgotti/rkt,nhlfr/rkt,rkt/rkt,kbrwn/rkt,krnowak/rkt,matthaias/rkt,alban/rkt,iaguis/rkt,endocode/rkt,achanda/rkt,Shashwatsh/rkt,il9ue/rkt,joshix/rkt,euank/rkt,markllama/rkt,ybubnov/rkt,liugenping/rkt,liugenping/rkt,monstermunchkin/rkt,adfernandes/rkt,endocode/rkt,akshaykarle/rkt,yifan-gu/rocket,yifan-gu/rocket,rkt/rkt,s-urbaniak/rkt,intelsdi-x/rkt,joshix/rkt,liubq919/rkt,s-urbaniak/rkt,yifan-gu/rkt,akshaykarle/rkt,shobhit85/rkt,linki/rkt,jonboulle/rkt,iaguis/rkt,lucasallan/rkt,achanda/rkt,sstabellini/rkt,matthaias/rkt,krnowak/rkt,liubq919/rkt,jonboulle/rkt,yifan-gu/rkt,sgotti/rkt,sinfomicien/rkt,sstabellini/rkt,jzelinskie/rkt,lucasallan/rkt,tmrts/rkt,kbrwn/rkt,Wilybald/rkt,krnowak/rkt,adfernandes/rkt,liugenping/rkt,Shashwatsh/rkt,blixtra/rkt,il9ue/rkt,euank/rkt,nhlfr/rkt,endocode/rkt,kinvolk/rkt,monstermunchkin/rkt,rkt/rkt,blixtra/rkt,kinvolk/rkt,squeed/rkt,Shashwatsh/rkt,jakon89/rkt,sgotti/rkt,markllama/rkt,ybubnov/rkt,cab105/rkt,jonboulle/rkt,tmrts/rkt,joshix/rkt,squeed/rkt,linki/rkt,shobhit85/rkt,cab105/rkt,jakon89/rkt,joshix/rkt,kinvolk/rkt,shobhit85/rkt,kbrwn/rkt,jasonchaffee/rkt,ybubnov/rkt,nhlfr/rkt,Wilybald/rkt,dgonyeo/rkt,jakon89/rkt,sinfomicien/rkt,liubq919/rkt,jasonchaffee/rkt,coreos/rkt,lucasallan/rkt,mike1729/rkt,jzelinskie/rkt,matthaias/rkt,achanda/rkt,monstermunchkin/rkt,squeed/rkt