Bump gitective to v0.9.54

Upgrade gitective to align the underlying JGit library to the same
v5.0.3 used in Gerrit 2.16-SNAPSHOT

Change-Id: I956d8994a61777bf83d31564c411cd2a787ccc56
diff --git a/build.sbt b/build.sbt
index f0cee33..6564192 100644
--- a/build.sbt
+++ b/build.sbt
@@ -15,7 +15,7 @@
     scalaVersion := "2.11.8",
 
     libraryDependencies ++= Seq(
-      "io.fabric8" % "gitective-core" % "0.9.37"
+      "io.fabric8" % "gitective-core" % "0.9.54"
         exclude ("org.eclipse.jgit", "org.eclipse.jgit"),
 
       "com.google.inject" % "guice" % "4.2.0" % Provided,
diff --git a/src/test/scala/com/googlesource/gerrit/plugins/analytics/test/CommitStatisticsSpec.scala b/src/test/scala/com/googlesource/gerrit/plugins/analytics/test/CommitStatisticsSpec.scala
index df4260a..b14bff8 100644
--- a/src/test/scala/com/googlesource/gerrit/plugins/analytics/test/CommitStatisticsSpec.scala
+++ b/src/test/scala/com/googlesource/gerrit/plugins/analytics/test/CommitStatisticsSpec.scala
@@ -46,7 +46,7 @@
     try {
       val commitToMerge = commit(committer, fname, content)
       checkout(currentBranch)
-      mergeBranch("tmp", true)
+      mergeBranch(tmpBranch.getName, true)
     } finally {
        deleteBranch(testRepo, tmpBranch.getName)
     }
diff --git a/src/test/scala/com/googlesource/gerrit/plugins/analytics/test/GitTestCase.scala b/src/test/scala/com/googlesource/gerrit/plugins/analytics/test/GitTestCase.scala
index 8a1dcf7..a511420 100644
--- a/src/test/scala/com/googlesource/gerrit/plugins/analytics/test/GitTestCase.scala
+++ b/src/test/scala/com/googlesource/gerrit/plugins/analytics/test/GitTestCase.scala
@@ -147,7 +147,7 @@
     */
   protected def deleteBranch(repo: File, name: String): String = {
     use(Git.open(repo)) { git =>
-      git.branchDelete().setBranchNames(name).call.get(0)
+      git.branchDelete().setBranchNames(name).setForce(true).call.get(0)
     }
   }