Trove image build fails getting percona key

This fails often in the gate and I ran into it migrating
trove-integration into trove-image-builder.

The most common cause for this is that keys.gnupg.net fails. While
there are multiple servers proxied for this service, sometimes they
fail. In general people have found keyserver.ubuntu.com to be more
reliable.

Change-Id: I97dcb9120c75129d8a0aaed9ddd39b9e5fa7e608
Closes-Bug: #1579094

scripts/files/elements/ubuntu-mariadb/pre-install.d/10-percona-apt-key

@@ -12,8 +12,23 @@ set -o xtrace
 # Add Percona GPG key
 mkdir -p /home/${GUEST_USERNAME}/.gnupg
 
+# sometimes the primary key server is unavailable and we should try an
+# alternate.  see
+# https://bugs.launchpad.net/percona-server/+bug/907789.  Disable
+# shell errexit so we can interrogate the exit code and take action
+# based on the exit code. We will reenable it later.
+set +e
 apt-key adv --keyserver hkp://keys.gnupg.net --recv-keys 1C4CBDCDCD2EFD2A
 
+if [ "$?" -ne "0" ];
+then
+    echo "Trying alternate keyserver hkp://keyserver.ubuntu.com"
+    set -e
+    apt-key adv --keyserver hkp://keyserver.ubuntu.com --recv-keys 1C4CBDCDCD2EFD2A
+fi
+
+set -e
+
 # Add Percona repo
 # Creates the Percona sources list
 cat <<EOL > /etc/apt/sources.list.d/percona.list

scripts/files/elements/ubuntu-mysql/pre-install.d/10-percona-apt-key

@@ -12,8 +12,23 @@ set -o xtrace
 # Add Percona GPG key
 mkdir -p /home/${GUEST_USERNAME}/.gnupg
 
+# sometimes the primary key server is unavailable and we should try an
+# alternate.  see
+# https://bugs.launchpad.net/percona-server/+bug/907789.  Disable
+# shell errexit so we can interrogate the exit code and take action
+# based on the exit code. We will reenable it later.
+set +e
 apt-key adv --keyserver hkp://keys.gnupg.net --recv-keys 1C4CBDCDCD2EFD2A
 
+if [ "$?" -ne "0" ];
+then
+    echo "Trying alternate keyserver hkp://keyserver.ubuntu.com"
+    set -e
+    apt-key adv --keyserver hkp://keyserver.ubuntu.com --recv-keys 1C4CBDCDCD2EFD2A
+fi
+
+set -e
+
 # Add Percona repo
 # Creates the percona sources list
 cat <<EOL > /etc/apt/sources.list.d/percona.list

scripts/files/elements/ubuntu-percona/pre-install.d/10-percona-apt-key

@@ -14,8 +14,23 @@ if [ ! -e /home/${GUEST_USERNAME}/.gnupg ]; then
     mkdir -p /home/${GUEST_USERNAME}/.gnupg
 fi
 
+# sometimes the primary key server is unavailable and we should try an
+# alternate.  see
+# https://bugs.launchpad.net/percona-server/+bug/907789.  Disable
+# shell errexit so we can interrogate the exit code and take action
+# based on the exit code. We will reenable it later.
+set +e
 apt-key adv --keyserver hkp://keys.gnupg.net --recv-keys 1C4CBDCDCD2EFD2A
 
+if [ "$?" -ne "0" ];
+then
+    echo "Trying alternate keyserver hkp://keyserver.ubuntu.com"
+    set -e
+    apt-key adv --keyserver hkp://keyserver.ubuntu.com --recv-keys 1C4CBDCDCD2EFD2A
+fi
+
+set -e
+
 # add Percona repo
 # creates the percona sources list
 cat <<EOL > /etc/apt/sources.list.d/percona.list

scripts/files/elements/ubuntu-pxc/pre-install.d/10-percona-apt-key

@@ -14,8 +14,23 @@ if [ ! -e /home/${GUEST_USERNAME}/.gnupg ]; then
     mkdir -p /home/${GUEST_USERNAME}/.gnupg
 fi
 
+# sometimes the primary key server is unavailable and we should try an
+# alternate.  see
+# https://bugs.launchpad.net/percona-server/+bug/907789.  Disable
+# shell errexit so we can interrogate the exit code and take action
+# based on the exit code. We will reenable it later.
+set +e
 apt-key adv --keyserver hkp://keys.gnupg.net --recv-keys 1C4CBDCDCD2EFD2A
 
+if [ "$?" -ne "0" ];
+then
+    echo "Trying alternate keyserver hkp://keyserver.ubuntu.com"
+    set -e
+    apt-key adv --keyserver hkp://keyserver.ubuntu.com --recv-keys 1C4CBDCDCD2EFD2A
+fi
+
+set -e
+
 # add Percona repo
 # creates the percona sources list
 cat <<EOL > /etc/apt/sources.list.d/percona.list