mirrors: remove is.mirror.flokinet (down for 4w, no op response in 3w)

Zero visible operator activity on github in the last year, two. The
other two mirrors on this domain might be zombies.

Closes #257

Author: tstein

mirrors/Makefile.am

@@ -23,7 +23,7 @@ pkgdata_EUROPE_MIRRORS = grimler.se			\
 packages.termux.dev termux.librehat.com \
 termux.mentality.rip mirrors.de.sahilister.net termux.cdn.lumito.net	\
 termux.3san.dev mirror.accum.se			\
-md.mirrors.hacktegic.com ftp.fau.de is.mirror.flokinet.net		\
+md.mirrors.hacktegic.com ftp.fau.de \
 ro.mirror.flokinet.net mirrors.medzik.dev	\
 mirror.sunred.org mirror.autkin.net mirror.bouwhuis.network		\
 ftp.agdsn.de	ftp.icm.edu.pl		        \
@@ -75,6 +75,7 @@ china/mirrors.ustc.edu.cn \
 china/mirrors.zju.edu.cn \
 chinese_mainland/mirrors.qvq.net.cn \
 europe/cdn.lumito.net \
+europe/is.mirror.flokinet.net \
 europe/mirror.leitecastro.com \
 europe/mirror.mwt.me \
 europe/mirror.polido.pt \