Add missing dependency; resolves VUFIND-1315.

Vagrantfile

@@ -41,7 +41,7 @@ Vagrant.configure("2") do |config|
     # Install package dependencies.
     apt-get update
     apt-get install -y git zip unzip apache2 default-jdk mysql-server
-    apt-get install -y libapache2-mod-php php-mbstring php-pear php php-dev php-gd php-intl php-json php-ldap php-mysql php-xml php-curl
+    apt-get install -y libapache2-mod-php php-mbstring php-pear php php-dev php-gd php-intl php-json php-ldap php-mysql php-soap php-xml php-curl
     
     # Install composer.
     php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"