fix: Check first in $PATH for nginx, use sbin location as backup

plugins/nginx-vhosts/functions

@@ -8,10 +8,14 @@ source "$PLUGIN_AVAILABLE_PATH/ps/functions"
 
 get_nginx_location() {
   declare desc="check that nginx is at the expected location and return it"
-  local NGINX_LOCATION="/usr/sbin/nginx"
-  if ! [[ -x "$NGINX_LOCATION" ]]; then
-    dokku_log_fail "Could not find nginx binary at ${NGINX_LOCATION}."
-    exit 1;
+  local NGINX_LOCATION=$(which nginx 2>/dev/null)
+
+  if [[ -z "$NGINX_LOCATION" ]]; then
+    NGINX_LOCATION="/usr/sbin/nginx"
+    if ! [[ -x "$NGINX_LOCATION" ]]; then
+      dokku_log_fail "Could not find nginx binary in \$PATH or at '${NGINX_LOCATION}'."
+      exit 1;
+    fi
   fi
   echo "$NGINX_LOCATION"
 }