title: Tests using embedded postgres fail with Illegal State Exception
body: <p>I'm running some tests against an embedded postgres database using otj-pg-embedded. While the tests run fine locally they fail when run by Gitlab-CI with an Illegal State Exception. 
  Gitlab CI builds it and runs tests that don't include otj-pg-embedded just fine.</p>
  
  <p>I've commented out most of the test class and pinpointed the problem to:  </p>
  
  <pre><code>public static SingleInstancePostgresRule pg = EmbeddedPostgresRules.singleInstance();
  </code></pre>
  
  <pre><code>import com.goldfinger.models.AuditLog;
  import com.opentable.db.postgres.embedded.FlywayPreparer;
  import com.opentable.db.postgres.junit.EmbeddedPostgresRules;
  import com.opentable.db.postgres.junit.PreparedDbRule;
  import org.junit.*;
  import org.junit.runner.RunWith;
  import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
  import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
  
  @RunWith(SpringJUnit4ClassRunner.class)
  public class SQLAuditRepositoryTest {
  
      private static SQLAuditRepository sqlAuditRepository;
      private static AuditLog auditLog_1;
      private static AuditLog auditLog_2;
      private static AuditLog auditLog_3;
      private static List&lt;AuditLog&gt; auditLogList;
  
      @ClassRule
          public static SingleInstancePostgresRule pg = EmbeddedPostgresRules.singleInstance();
  
  
      @Test
      public void simpleTest() {
          assert (2 == 2);
      }
  }
  </code></pre>
  
  <p>This is the stack trace:</p>
  
  <pre><code>java.lang.IllegalStateException: Process [/tmp/embedded-pg/PG-06e3a92a2edb6ddd6dbdf5602d0252ca/bin/initdb, -A, trust, -U, postgres, -D, /tmp/epg6584640257265165384, -E, UTF-8] failed
  
      at com.opentable.db.postgres.embedded.EmbeddedPostgres.system(EmbeddedPostgres.java:626)
      at com.opentable.db.postgres.embedded.EmbeddedPostgres.initdb(EmbeddedPostgres.java:240)
  ...
  ... many lines here
  ...
      at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
      at java.lang.Thread.run(Thread.java:745)
  </code></pre>
  
  <p>This is the gitlab-ci.yml</p>
  
  <pre><code>image: java:latest
  services:
    - postgres:latest
  before_script:
    - export GRADLE_USER_HOME=`pwd`/.gradle
  
  package:
    stage: build
    script:
      - ./gradlew assemble
  
  test:
    stage: test
    script:
    - ./gradlew check
    artifacts:
      reports:
        junit: build/test-results/test/*.xml
  
  
  </code></pre>
  
  <p>Any help will be appreciated.</p>