Update nginx config only if its present

install

@@ -302,6 +302,8 @@ function ee_update_latest()
             fi
         fi
     fi
+
+    if [ -f /etc/nginx/nginx.conf ]; then
         ee_lib_echo "Updating Nginx configuration, please wait..."
         # From version 3.1.10 we are using Suse builder for repository
         if [ "$ee_distro_version" == "precise" ]; then
@@ -375,6 +377,7 @@ function ee_update_latest()
                 apt-get -o Dpkg::Options::="--force-confmiss" -o Dpkg::Options::="--force-confold" -y install nginx-custom
             fi
         fi
+    fi
 
     if [ -f /etc/nginx/nginx.conf ]; then
         sed -i "s/.*X-Powered-By.*/\tadd_header X-Powered-By \"EasyEngine $ee_version_new\";/" /etc/nginx/nginx.conf &>> /dev/null