Fix JGit set core.fileMode to false by default instead of true for non Windows OS.

Issue 519887

Signed-off-by: Joan <joan@goyeau.com>

org.eclipse.jgit/src/org/eclipse/jgit/util/FS_POSIX.java

@@ -188,7 +188,7 @@ public class FS_POSIX extends FS {
 		if (!isFile(f))
 			return false;
 		if (!canExecute)
-			return f.setExecutable(false);
+			return f.setExecutable(false, false);
 
 		try {
 			Path path = f.toPath();