Be sure to close() file descriptor on error case

In receivelog.c:writeTimeLineHistoryFile(), we were not properly
closing the open'd file descriptor in error cases.  While this
wouldn't matter much if we were about to exit due to such an
error, that's not the case with pg_receivexlog as it can be a
long-running process and these errors are non-fatal.

This resource leak was found by the Coverity scanner.

Back-patch to 9.3 where this issue first appeared.

src/bin/pg_basebackup/receivelog.c

@@ -329,6 +329,7 @@ writeTimeLineHistoryFile(char *basedir, TimeLineID tli, char *filename, char *co
 		/*
 		 * If we fail to make the file, delete it to release disk space
 		 */
+		close(fd);
 		unlink(tmppath);
 		errno = save_errno;
 
@@ -339,6 +340,7 @@ writeTimeLineHistoryFile(char *basedir, TimeLineID tli, char *filename, char *co
 
 	if (fsync(fd) != 0)
 	{
+		close(fd);
 		fprintf(stderr, _("%s: could not fsync file \"%s\": %s\n"),
 				progname, tmppath, strerror(errno));
 		return false;