Fix RawText.getLineDelimiter() for empty first line

Bug: 456776
Change-Id: Iae50be89ea6d5aee33bd938a937ac5ca578aabca
Signed-off-by: Frank Wagner <frank.wagner@fr.ibm.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/diff/RawTextTest.java

@@ -230,6 +230,13 @@ public class RawTextTest {
 		assertFalse(rt.isMissingNewlineAtEnd());
 	}
 
+	@Test
+	public void testLineDelimiter2() throws Exception {
+		RawText rt = new RawText(Constants.encodeASCII("\nfoo"));
+		assertEquals("\n", rt.getLineDelimiter());
+		assertTrue(rt.isMissingNewlineAtEnd());
+	}
+
 	private static RawText t(String text) {
 		StringBuilder r = new StringBuilder();
 		for (int i = 0; i < text.length(); i++) {

org.eclipse.jgit/src/org/eclipse/jgit/diff/RawText.java

@@ -289,7 +289,7 @@ public class RawText extends Sequence {
 		int e = getEnd(0);
 		if (content[e - 1] != '\n')
 			return null;
-		if (content.length > 1 && content[e - 2] == '\r')
+		if (content.length > 1 && e > 1 && content[e - 2] == '\r')
 			return "\r\n"; //$NON-NLS-1$
 		else
 			return "\n"; //$NON-NLS-1$