functional tests: increase timeout to 60min
functional tests: increase timeout to 60min

Some of our Jenkins machines reach the previous 45min limit, let's
increase it a bit more.

sgotti/rkt,joshix/rkt,sstabellini/rkt,sgotti/rkt,achanda/rkt,squeed/rkt,ybubnov/rkt,lucasallan/rkt,lucasallan/rkt,tmrts/rkt,dgonyeo/rkt,jjlakis/rkt,mike1729/rkt,s-urbaniak/rkt,mike1729/rkt,coreos/rkt,shobhit85/rkt,kinvolk/rkt,monstermunchkin/rkt,tmrts/rkt,yifan-gu/rocket,jjlakis/rkt,jakon89/rkt,euank/rkt,jonboulle/rkt,yifan-gu/rkt,Wilybald/rkt,euank/rkt,monstermunchkin/rkt,yifan-gu/rocket,Wilybald/rkt,cab105/rkt,Wilybald/rkt,jakon89/rkt,alban/rkt,nhlfr/rkt,lucasallan/rkt,cab105/rkt,joshix/rkt,s-urbaniak/rkt,alban/rkt,yifan-gu/rkt,jjlakis/rkt,tmrts/rkt,joshix/rkt,sstabellini/rkt,kinvolk/rkt,kinvolk/rkt,cab105/rkt,akshaykarle/rkt,achanda/rkt,euank/rkt,sstabellini/rkt,rkt/rkt,Shashwatsh/rkt,rkt/rkt,lucasallan/rkt,jonboulle/rkt,Shashwatsh/rkt,ybubnov/rkt,coreos/rkt,yifan-gu/rkt,achanda/rkt,Shashwatsh/rkt,coreos/rkt,dgonyeo/rkt,mike1729/rkt,ybubnov/rkt,shobhit85/rkt,monstermunchkin/rkt,s-urbaniak/rkt,shobhit85/rkt,alban/rkt,jakon89/rkt,intelsdi-x/rkt,kinvolk/rkt,dgonyeo/rkt,squeed/rkt,joshix/rkt,akshaykarle/rkt,nhlfr/rkt,intelsdi-x/rkt,sgotti/rkt,rkt/rkt,akshaykarle/rkt,nhlfr/rkt,squeed/rkt,Wilybald/rkt,rkt/rkt,intelsdi-x/rkt,yifan-gu/rocket,jonboulle/rkt