Fixed cleanup of stale cfbuild packages on build hosts

zypper has no uninstall command, so erase-packages silently did nothing
on SUSE. The || true guard hid the error.

The cleanup also ran too late. It sat inside the cf-remote branch, which
the CentOS 6 and SUSE 12 paths never reach because they install the
agent directly.

Leftover cfbuild-* packages own files under /var/cfengine. Installing
cfengine-nova then aborts on file conflicts, because zypper install -y
does not auto-answer the file conflict prompt.

Signed-off-by: Lars Erik Wik <lars.erik.wik@northern.tech>

Author: larsewi

ci/setup-cfengine-build-host.sh

@@ -149,14 +149,15 @@ if [ -f /etc/os-release ]; then
     elif grep -q suse /etc/os-release; then
         zypper -n update
         alias software='zypper install -y'
-        alias erase-packages='zypper uninstall -y'
+        alias erase-packages='zypper remove -y'
     else
         echo "Unknown platform ID $ID. Need this information in order to update/upgrade distribution packages."
         exit 1
     fi
 elif [ -f /etc/redhat-release ]; then
     yum update --assumeyes
     alias software='yum install --assumeyes'
+    alias erase-packages='yum erase --assumeyes'
 else
     echo "No /etc/os-release or /etc/redhat-release so cant determine platform."
     exit 1
@@ -171,6 +172,11 @@ else
     exit 1
 fi
 
+# Must run before any cfengine-nova install below. The cfbuild-* packages own
+# files under /var/cfengine, so leftovers make the agent install fail on file
+# conflicts.
+erase-packages cfbuild-* || true # in case a dirty build was left on a long-living build host
+
 if grep -q 6.10 /etc/issue 2>/dev/null; then
     # special case of centos-6, cf-remote depends on urllib3 which depends on openssl 1.1.1+ that is not available
     # generally we rely on cf-remote to install cfengine-nova and download masterfiles so here we must provide for both of those
@@ -282,9 +288,6 @@ if ! /var/cfengine/bin/cf-agent -V 2>/dev/null; then
         mv "$HOME"/.cfengine/cf-remote/* "$HOME"/.config/cfengine/cf-remote/
     fi
 
-
-    erase-packages cfbuild-* || true # in case a dirty build was left on a long-living build host
-
     # We are passing a two-token string and need it to stay two tokens for proper argument parsing in $_VERSION
     # shellcheck disable=SC2086
     cf-remote --log-level info $_VERSION install --clients localhost || true