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
diff --git a/org.eclipse.scout.sdk/pom.xml b/org.eclipse.scout.sdk/pom.xml
index 35448fd..af76b9b 100644
--- a/org.eclipse.scout.sdk/pom.xml
+++ b/org.eclipse.scout.sdk/pom.xml
@@ -57,6 +57,7 @@
     <org.eclipse.scout.rt_version>6.1.0-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_6.1.x</sonar.branch>