Since revision 32, guix-data-service starts immediately but returns an HTTP
error code until initialization is complete. Adjust the test accordingly, and
remove the increased startup time limit.
* gnu/services/guix.scm (guix-data-service): Use default #:pid-file-timeout.
* gnu/tests/guix.scm (guix-data-service): Retry the http-get test several
times to give the service time to initialize.
Signed-off-by: Christopher Baines <mail@cbaines.net>