libhb: fix hb_vfr_info() and refactor hb_vfr_init() a bit.

Since SVN revision 5058, hb_vfr_init didn't have access to title->rate, rate_base - which are needed to set the input framerate for CFR/PFR. It was therefore printing the output framerate in both cases, regardless of the input framerate:

[22:13:04]    + frame rate: 23.976 fps -> constant 30.000 fps
[22:13:04]    + filters
[22:13:04]      + Framerate Shaper (1:27000000:900000)
[22:13:04]        + frame rate: 30.000 fps -> constant 30.000 fps



git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@5499 b64f7644-9d1e-0410-96f1-a4d463321fa5