qemurunner: Tweak qemu pid starting timeout code

qemurunner: Tweak qemu pid starting timeout code

We're seeing timeouts in the autobuilder testing code. Increase these
timeouts to 120, print the length of time we're having to wait, change
the error messages to really be errors and don't print empty logs, its
not helpful, print a message about the empty log instead.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>