Make coverity: do all compiles as one scan-build run

In fed10192, the coverity build process
was modified to split out the build logs into separate files, instead of
having one log file that gets overwritten repeatedly, making failures
hard to debug.

However, the coverity service gets upset if there is no file named with
the expected build log name. Therefore, instead, we'll capture the
python bits first, and then capture all the compilation bits in one
cov-build command.

PR: !273
Signed-off-by: Steve Beattie <steve.beattie@canonical.com>
Acked-by: Christian Boltz <apparmor@cboltz.de>
2 jobs from master in 10 minutes and 9 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #128115509
build-all

00:02:49

 
  Test
passed #128115510
test-all

00:07:20