Revert jgit version to 3.7.1

JGit changed APIs as well as the source level to Java 7 in 4.x.
Sadly, maven-scm-provider-jgit is not compatible with this.

Change-Id: I6b57758f11a9c807cf9322b31944bd16890447fb
diff --git a/maven_plugin_version-master/pom.xml b/maven_plugin_version-master/pom.xml
index 7d7a4fe..3fef1c9 100644
--- a/maven_plugin_version-master/pom.xml
+++ b/maven_plugin_version-master/pom.xml
@@ -356,7 +356,7 @@
             <dependency>
               <groupId>org.eclipse.jgit</groupId>
               <artifactId>org.eclipse.jgit</artifactId>
-              <version>4.5.1.201703201650-r</version>
+              <version>3.7.1.201504261725-r</version>
             </dependency>
           </dependencies>
         </plugin>