slparunner: document the reasons why we keep srv//slaprunner

software/slaprunner/buildout.hash.cfg

@@ -18,7 +18,7 @@ md5sum = c44a7481bb85e3258128afe3fcf23f44
 
 [template-runner]
 filename = instance-runner.cfg
-md5sum = 58a6f21021279ae52c91813f61cdbdd7
+md5sum = 4923167fe68c8c20aff46dbeb3716f9b
 
 [template-runner-import-script]
 filename = template/runner-import.sh.jinja2

software/slaprunner/instance-runner.cfg

@@ -120,6 +120,10 @@ recipe = slapos.cookbook:mkdirectory
 home = $${buildout:directory}
 etc = $${:home}/etc/
 var = $${:home}/var/
+# This srv path has an extra slash, which will cause runnerdirectory:home
+# to be .../srv//runner/.. but for compatibility reasons we don't fix this,
+# because this is the path that will be used as software URL installed by
+# webrunner and would cause software release hash to become different.
 srv = $${:home}/srv/
 bin = $${:home}/bin/
 tmp = $${:home}/tmp/