concurrencykit: drop trailing continuation character in do_configure

* with newer bitbake it parses it differently and task fails:
  concurrencykit/0.4.3+gitAUTOINC+900d203aa9-r0/temp/run.do_configure.13244:
  Syntax error: end of file unexpected (expecting "}")

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>