test: allow unsigned extensions in automated tests

Seems like the updated p4d packages now require signed packages, so we must
set the configurable to allow unsigned packages, since the HAS extension is
not yet signed (and probably will not be signed during testing).

test/install/CentOS8.dockerfile

@@ -18,7 +18,7 @@ enabled=1\n\
 gpgcheck=1\n'\
 >> /etc/yum.repos.d/perforce.repo
 # temporary work-around for broken package dependencies
-RUN yum -q -y install helix-cli-2020.2-2112800.x86_64 helix-p4d
+RUN yum -q -y install helix-cli-2021.1-2126753.x86_64 helix-p4d
 
 # patch configure script to wait for p4d to start fully (P4-20611)
 COPY containers/configure.diff /tmp

test/install/runtest.sh

@@ -16,7 +16,8 @@ p4dctl start -o '-p 0.0.0.0:1666' despot
 echo ${P4PASSWD} | p4 login
 
 # disable the signed extensions requirement for testing
-# p4 configure set server.extensions.allow.unsigned=1
+# (since at least version P4D/LINUX26X86_64/2021.1/2126753)
+p4 configure set server.extensions.allow.unsigned=1
 
 # create a group with long lived tickets, log in again
 p4 group -i <<EOT