[PB] Bump base for HB 2.6.1 (#5279)
[PB] Bump base for HB 2.6.1 (#5279)

Not broken on gcc 4.8 anymore. See <https://github.com/koreader/koreader-base/pull/959>.
NiLuJe/koreader,NiLuJe/koreader,poire-z/koreader,Markismus/koreader,mwoz123/koreader,koreader/koreader,Frenzie/koreader,koreader/koreader,poire-z/koreader,mihailim/koreader,pazos/koreader,Hzj-jie/koreader,Frenzie/koreader