Add config constant for "mergeoptions"

Bug: 336933
Change-Id: Idcc0fbc8a8143dd665e80e4d6f4a4adaeae287db
Signed-off-by: Chris Aniszczyk <zx@twitter.com>

org.eclipse.jgit/src/org/eclipse/jgit/lib/ConfigConstants.java

@@ -187,4 +187,7 @@ public class ConfigConstants {
 
 	/** The "pruneexpire" key */
 	public static final String CONFIG_KEY_PRUNEEXPIRE = "pruneexpire";
+
+	/** The "mergeoptions" key */
+	public static final String CONFIG_KEY_MERGEOPTIONS = "mergeoptions";
 }