Fix typo in "Gerrit-Module"

In I239d93a435 Bazel build was fixed to consume resemblejs
dependency from gerrit core, but introduced a typo in package
name of gerrit module.

Bug: Issue 9911
Change-Id: I6c3108ad0ab3964186b811dd9ff1038fcda67bdc

BUILD

diff --git a/BUILD b/BUILD
index edd94b3..f68cdaf 100644
--- a/BUILD
+++ b/BUILD
@@ -7,7 +7,7 @@
     srcs = ["java/com/googlesource/gerrit/plugins/imagediff/ImageDiffModule.java"],
     manifest_entries = [
         "Gerrit-PluginName: image-diff",
-        "Gerrit-Module: com.googlesource.gerrit.plugins.codemirror.ImageDiffModule",
+        "Gerrit-Module: com.googlesource.gerrit.plugins.imagediff.ImageDiffModule",
         "Implementation-Title: Image Diff plugin",
     ],
     resource_jars = [":image-diff-static"],