MCOL-4535: Clean up libreadline as ColumnStore no longer needs it

Keep the readline installation step in Salsa-CI stages that install
MariaDB.org packages in Debian Sid (or releases after is, such as
Debian 11 "Bullseye" or Ubuntu 21.04 "Hirsute") as those old packages
still depend on readline for the MariaDB Server itself.

debian/autobake-deb.sh

@@ -24,14 +24,6 @@ then
   echo >> debian/control
   cat storage/columnstore/columnstore/debian/control >> debian/control
 
-  # From Debian Bullseye/Ubuntu Hirsute onwards libreadline is gone, so build with it
-  # only on older releases where it is still available. This can be removed once
-  # MCOL-4535 lands in MariaDB.
-  if apt-cache madison libreadline-gplv2-dev | grep 'libreadline-gplv2-dev' >/dev/null 2>&1
-  then
-    sed 's/libpcre2-dev,/libpcre2-dev, libreadline-gplv2-dev [amd64],/' -i debian/control
-  fi
-
   # ColumnStore is explcitly disabled in the native build, so allow it now
   # when build it when triggered by autobake-deb.sh
   sed '/-DPLUGIN_COLUMNSTORE=NO/d' -i debian/rules

debian/salsa-ci.yml

@@ -37,14 +37,6 @@ build:
     - apt-get update && eatmydata apt-get install --yes --no-install-recommends aptitude devscripts ccache equivs
     - cd ${WORKING_DIR}/${SOURCE_DIR}
     - eatmydata install-build-deps.sh .
-    - |
-      # From Debian Bullseye/Ubuntu Hirsute onwards libreadline is gone, so build with it
-      # only on older releases where it is still available. This can be removed once
-      # MCOL-4535 lands in MariaDB.
-      if apt-cache madison libreadline-gplv2-dev | grep 'libreadline-gplv2-dev' >/dev/null 2>&1
-      then
-       apt-get install --yes libreadline-gplv2-dev
-      fi
     - update-ccache-symlinks; ccache -z # Zero out ccache counters
     - while true; do sleep 600; echo "10 minutes passed" >&2; done & # Progress keeper since build is long and silent
     - debian/autobake-deb.sh |& tail -n 10000 # Keep Gitlab-CI output under 4 MB