Handle the text and src_file the same way in the BPF constructor
Handle the text and src_file the same way in the BPF constructor

Instead of having two different code paths for code passed in as a
string (via the text parameter) and code passed in via file (via the
src_file parameter), load the contents of src_file into the text
variable and handle both in the same code path.
This fixes issue #2385.

tuxology/bcc,iovisor/bcc,brendangregg/bcc,tuxology/bcc,tuxology/bcc,iovisor/bcc,brendangregg/bcc,tuxology/bcc,brendangregg/bcc,brendangregg/bcc,brendangregg/bcc,tuxology/bcc,iovisor/bcc,iovisor/bcc,iovisor/bcc