software/seleniumserver: fix maxSession

`maxSession` is a selenium node option

software/seleniumserver/buildout.hash.cfg

@@ -19,4 +19,4 @@ md5sum = 58f6d112c90a23ae39f07a96fa5c8f1c
 
 [template-selenium]
 filename = instance-selenium.cfg.in
-md5sum = 906abd81b5e7f2cf7a72883f5da126fe
+md5sum = 7d8bdc03f8feadc83d70f71df2ebb42d

software/seleniumserver/instance-selenium.cfg.in

@@ -55,7 +55,6 @@ command-line =
     -host $${:hostname}
     -port $${:port}
     -role hub
-    -maxSession {{ parameter_dict['slotQuantity'] }}
     -newSessionWaitTimeout 600000
     --debug
 
@@ -83,6 +82,7 @@ command-line =
     -host $${:hostname}
     -port $${:port}
     -role node
+    -maxSession {{ parameter_dict['slotQuantity'] }}
     -timeout 300
     -hub $${selenium-server-hub-instance:register-url}
     -capabilities $${:capabilities}