add missing config.h to r2ioabs.c
add missing config.h to r2ioabs.c

git-svn-id: e22e7ba13cdef0ce65536ff79bba069cc1048473@364 c87312dc-f89b-4d16-81b4-35530099f826

moises-silva/openr2,moises-silva/openr2,moises-silva/openr2