MINOR: checks: Use ver keyword to specify the HTTP version for http checks

'ver' keyword is already used by sample fetches while 'vsn' is not used anywhere
else. So better to use 'ver' too for http-check send rules.
diff --git a/reg-tests/checks/http-check.vtc b/reg-tests/checks/http-check.vtc
index 7d8d514..057484f 100644
--- a/reg-tests/checks/http-check.vtc
+++ b/reg-tests/checks/http-check.vtc
@@ -103,7 +103,7 @@
     backend be3
         log ${S1_addr}:${S1_port} len 2048 local0
         option httpchk
-        http-check send meth GET uri /status vsn HTTP/1.1
+        http-check send meth GET uri /status ver HTTP/1.1
         server srv ${s3_addr}:${s3_port} check inter 100ms rise 1 fall 1
 
     backend be4
@@ -113,11 +113,11 @@
         http-check send-state
         http-check connect addr ${s4_addr}:${s4_port}
         http-check set-var(check.server) "str(srv)"
-        http-check send meth GET uri /req1 vsn HTTP/1.1 hdr x-test "server=%[var(check.server)]"
+        http-check send meth GET uri /req1 ver HTTP/1.1 hdr x-test "server=%[var(check.server)]"
         http-check expect status 200
         http-check connect addr ${s4_addr} port ${s4_port}
         http-check unset-var(check.server)
-        http-check send meth GET uri /req2 vsn HTTP/1.1 hdr x-test "server=%[var(check.server)]" body "health-check body"
+        http-check send meth GET uri /req2 ver HTTP/1.1 hdr x-test "server=%[var(check.server)]" body "health-check body"
         http-check expect rstatus "^2[0-9]{2}"
         http-check connect addr ${s4_addr} port ${s4_port}
         http-check send meth GET uri /req3