testing: Switched PTS measurements to /usr/sbin

Due to Debian 10 linking /bin to /usr/bin which drastically
increased the number of files in /bin, the PTS measurement
was switched to /usr/sbin with a lesser number of files.

testing/tests/tnc/tnccs-20-pts-no-ecc/hosts/carol/etc/strongswan.conf

@@ -12,6 +12,11 @@ charon-systemd {
       pts = 3
     }
   }
+  plugins {
+    eap-ttls {
+      max_message_count = 0
+    }
+  }
 }
 
 libtls {

testing/tests/tnc/tnccs-20-pts-no-ecc/hosts/dave/etc/strongswan.conf

@@ -13,6 +13,9 @@ charon-systemd {
     }
   }
   plugins {
+    eap-ttls {
+      max_message_count = 0
+    }
     tnc-imc {
       preferred_language = de
     }

testing/tests/tnc/tnccs-20-pts-no-ecc/hosts/moon/etc/strongswan.conf

@@ -14,6 +14,7 @@ charon-systemd {
   }
   plugins {
     eap-ttls {
+      max_message_count = 0
       phase2_method = md5
       phase2_piggyback = yes
       phase2_tnc = yes