[sfDoctrineRestGeneratorPlugin]: fixed a deserialization error when passing an empty XML tag
[sfDoctrineRestGeneratorPlugin]: fixed a deserialization error when passing an empty XML tag

git-svn-id: 47f39bd1a2e701b74bb9d256998bb3928a7fe1f0@32099 ee427ae8-e902-0410-961c-c3ed070cd9f9

Recras/sfDoctrineRestGeneratorPlugin,stadline/sfDoctrineRestGeneratorPlugin,xavierlacot/sfDoctrineRestGeneratorPlugin