travis: set SPECL correctly.

* .travis.yml (script): Set SPECL correctly.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
configury: bump bootstrap specl build requirement to master.

* bootstrap.conf (buildreq): Bump specl requirement to 'git'
revision, which will eventually be release 12.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>