m4/.gitignore: Remove stray blank line.
diff --git a/m4/.gitignore b/m4/.gitignore
index 8bab51c..38066dd 100644
--- a/m4/.gitignore
+++ b/m4/.gitignore
@@ -3,4 +3,3 @@
 ltsugar.m4
 ltversion.m4
 lt~obsolete.m4
-