test/Makefile.am: include manpage-scan.pl and nroff-scan.pl in dist

Reported-by: Ray Satiro
Bug: https://curl.haxx.se/mail/lib-2016-05/0113.html

tests/Makefile.am

@@ -28,7 +28,8 @@ EXTRA_DIST = ftpserver.pl httpserver.pl secureserver.pl runtests.pl getpart.pm \
  sshserver.pl sshhelp.pm pathhelp.pm testcurl.1 runtests.1 \
  $(HTMLPAGES) $(PDFPAGES) \
  serverhelp.pm tftpserver.pl rtspserver.pl directories.pm symbol-scan.pl \
- CMakeLists.txt mem-include-scan.pl valgrind.supp http_pipe.py extern-scan.pl
+ CMakeLists.txt mem-include-scan.pl valgrind.supp http_pipe.py extern-scan.pl \
+ manpage-scan.pl nroff-scan.pl
 
 DISTCLEANFILES = configurehelp.pm