Add gitignore to constants

Bug: 291133
Change-Id: I24272d029cff446ffc80063870478577d628f338
Reviewed-by: Alex Blewitt <alex.blewitt@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

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

@@ -255,6 +255,9 @@ public final class Constants {
 	/** Beginning of the common "Signed-off-by: " commit message line */
 	public static final String SIGNED_OFF_BY_TAG = "Signed-off-by: ";
 
+	/** A gitignore file name */
+	public static final String GITIGNORE_FILENAME = ".gitignore";
+
 	/**
 	 * Create a new digest function for objects.
 	 *