Bug 549754: Reduce fork count to one (single vm)

Default in MavenMaster is a factor of 0.5 times the number of CPU cores.
After discussion, the parallel execution is not necessary, so we fix
this to "1".

Apply this change also for sdk

Change-Id: Ie6804708320a322a238c2e7e373fa9eb7ee5d1e5

org.eclipse.scout.sdk/pom.xml

@@ -57,6 +57,7 @@
     <org.eclipse.scout.rt_version>6.0.300-SNAPSHOT</org.eclipse.scout.rt_version>
 
     <master_coverage_jacoco_destFile>${basedir}/../org.eclipse.scout.sdk/target/jacoco-all.exec</master_coverage_jacoco_destFile>
+    <master_test_forkCount>1</master_test_forkCount>
     <!-- Sonar properties -->
     <sonar.branch>releases_6.0.x</sonar.branch>
     <master_test_timeout>1800</master_test_timeout>