Fix error caught by Travis CI

- Remove duplicate `threaded` tag
- Put maintainers in one line

library/perl

@@ -1,5 +1,4 @@
-Maintainers: Peter Martini <[email protected]> (@PeterMartini),
-             Zak B. Elep <[email protected]> (@zakame)
+Maintainers: Peter Martini <[email protected]> (@PeterMartini), Zak B. Elep <[email protected]> (@zakame)
 GitRepo: https://github.com/perl/docker-perl.git
 GitCommit: 904ec9505b3d6b71e559d7e1c1d9629a15e3f2ef
 
@@ -12,7 +11,7 @@ Directory: 5.026.000-64bit,threaded
 Tags: 5.24, 5.24.2
 Directory: 5.024.002-64bit
 
-Tags: threaded, 5-threaded, 5.24-threaded, 5.24.2-threaded
+Tags: 5-threaded, 5.24-threaded, 5.24.2-threaded
 Directory: 5.024.002-64bit,threaded
 
 Tags: 5.22, 5.22.4