runtime tests setup does not get architecture string right

This has been fiddled with several times, but is not working as is.

The prototype spec file (lsb-test-core.spec.sed) is modified when building
the real one with a sed instruction. Information from the specfile is
used in building the installable file setup_tests. This will in turn
be used in building the configuration file for the tests, and sets a
string that is emitted in the journal of each run in order to mark what
test it was generated by.

setup_tests currently ends up containing:

# Template marker for version in journal file
BUILD_VERSION="4.1.91-0.20140405.1 (%{_arch})"

and so the journal ends up with:

30||VSX_NAME=LSB Certification Version 4.1.91-0.20140405 (%{_arch})

Clearly, the intent was to get a readable string for the architecture
in there.