We should remove old verify key before installing a new one

common.xml

@@ -638,6 +638,7 @@ rm /lib/systemd/system/build
 
  <target name="install-verify-key">
   <antcall target="mount"/>
+  <delete file="${sysdir}/etc/mender/verify.key"/>
   <exec executable="openssl" failonerror="true">
    <arg line="rsa -in ${basedir}/host/private.key -out ${sysdir}/etc/mender/verify.key -pubout"/>
   </exec>