Fix stamping to produce stable file timestamps

Change-Id: I628ab5feb4a70f81ec832f1b81d1ad3a9caca615
diff --git a/org.eclipse.jgit/BUILD b/org.eclipse.jgit/BUILD
index 2083372..04873b0 100644
--- a/org.eclipse.jgit/BUILD
+++ b/org.eclipse.jgit/BUILD
@@ -38,7 +38,7 @@
         "cd $$TMP",
         "unzip -q $$ROOT/$<",
         "echo \"Implementation-Version: $$GEN_VERSION\n$$(cat META-INF/MANIFEST.MF)\" > META-INF/MANIFEST.MF",
-        "find . -exec touch '{}' ';'",
+        "find . -exec touch -t 198001010000 '{}' ';'",
         "zip -Xqr $$ROOT/$@ .",
         "rm -rf $$TMP",
     ]),