add missing semicolon ;-)

Signed-off-by: tgfrerer <tim@poniesandlight.co.uk>
fix RPi critical compilation issue

this fixes an issue where openFrameworksLib on RPi wouldn't compile due to an #ifdef out-scoping the variable "bpp" in ofGstVideoGrabber:

"variable 'bpp' not declared"

I've pulled out the bpp declaration & initialisation to be outside the #ifdef block, please @arturoc check if that's not completely whacky.

Signed-off-by: tgfrerer <tim@poniesandlight.co.uk>
Merge pull request #2193 from tgfrerer/fix_rpiCompilationIssues

Fix rpi compilation issues