Only change pam values when needed

src/freedombone-utils-setup

@@ -458,13 +458,17 @@ function set_max_login_tries {
     if ! grep -q ' deny=' /etc/pam.d/common-auth; then
         sed -i "/pam_deny.so/a auth    required\t\t\tpam_tally.so    onerr=fail no_lock_time per_user deny=$max_tries" /etc/pam.d/common-auth
     else
-        sed -i "s| deny=.*| deny=$max_tries|g" /etc/pam.d/common-auth
+        if ! grep -q " deny=$max_tries" /etc/pam.d/common-auth; then
+            sed -i "s| deny=.*| deny=$max_tries|g" /etc/pam.d/common-auth
+        fi
     fi
 
     if ! grep -q ' deny=' /etc/pam.d/common-account; then
         sed -i '/pam_deny.so/a account required\t\t\tpam_tally.so' /etc/pam.d/common-account
     else
-        sed -i "s| deny=.*| deny=$max_tries|g" /etc/pam.d/common-account
+        if ! grep -q " deny=$max_tries" /etc/pam.d/common-account; then
+            sed -i "s| deny=.*| deny=$max_tries|g" /etc/pam.d/common-account
+        fi
     fi
 }
 
@@ -630,7 +634,9 @@ function dummy_nologin_command {
 }
 
 function disable_null_passwords {
-    sed -i 's| nullok_secure||g' /etc/pam.d/common-auth
+    if grep -q ' nullok_secure' /etc/pam.d/common-auth; then
+        sed -i 's| nullok_secure||g' /etc/pam.d/common-auth
+    fi
 }
 
 function create_usb_canary {