moving eecf35c-backports.zip fix for seccomp/join bug in etc-fixes

etc-fixes/seccomp-join-bug/README

@@ -0,0 +1,11 @@
+These are patches for various Firejail versions for the security bug reported by Austin Morton
+on May 21, 2019:
+
+    Seccomp filters are copied into /run/firejail/mnt, and are writable
+    within the jail. A malicious process can modify files from inside the
+    jail. Processes that are later joined to the jail will not have seccomp
+    filters applied.
+
+The original discussion thread: https://github.com/netblue30/firejail/issues/2718
+The fix on mainline: https://github.com/netblue30/firejail/commit/eecf35c2f8249489a1d3e512bb07f0d427183134
+