proftpd: stick with openssl 1.0 for now

once a release including https://github.com/proftpd/proftpd/issues/674
is made we can update to openssl 1.1

/reviewed-on !460

component/proftpd/buildout.cfg

@@ -24,6 +24,9 @@ recipe = collective.recipe.grp
 recipe = slapos.recipe.cmmi
 md5sum = 13270911c42aac842435f18205546a1b
 url = ftp://ftp.proftpd.org/distrib/source/proftpd-1.3.6.tar.gz
+# 1.3.6 is not compatible with openssl 1.1.x
+# https://github.com/proftpd/proftpd/issues/674
+# (fix is in master, we are waiting for next release)
 configure-options =
   --enable-openssl
   --enable-nls
@@ -36,8 +39,8 @@ environment =
   LDFLAGS=${:ldflags}
   install_user=${proftpd-environment:USER}
   install_group=${proftpd-grp:GROUP}
-cppflags=-I${zlib:location}/include -I${openssl:location}/include
-ldflags=-L${zlib:location}/lib -Wl,-rpath=${zlib:location}/lib -L${openssl:location}/lib -Wl,-rpath=${openssl:location}/lib
+cppflags=-I${zlib:location}/include -I${openssl-1.0:location}/include
+ldflags=-L${zlib:location}/lib -Wl,-rpath=${zlib:location}/lib -L${openssl-1.0:location}/lib -Wl,-rpath=${openssl-1.0:location}/lib
 patch-binary = ${patch:location}/bin/patch
 patch-options = -p1
 patches =