explicitly cast to std::vector<double> to make gcc6 happy
With gcc6, compiling image_publisher fails with this error:
`
/[...]/image_publisher/src/nodelet/image_publisher_nodelet.cpp: In member function 'virtual void image_publisher::ImagePublisherNodelet::onInit()':/[...]/image_publisher/src/nodelet/image_publisher_nodelet.cpp:180:43: error: ambiguous overload for 'operator=' (operand types are 'sensor_msgs::CameraInfo\_<std::allocator<void>>::_D_type {aka std::vector<double>}' and 'boost::assign_detail::generic_list<int>')
camera_info\_.D = list_of(0)(0)(0)(0)(0);
`
After adding an initial explicit type cast for the assignment,
compiling fails further with:
`
| /[...]/image_publisher/src/nodelet/image_publisher_nodelet.cpp: In member function 'virtual void image_publisher::ImagePublisherNodelet::onInit()':
| /[...]/image_publisher/src/nodelet/image_publisher_nodelet.cpp:180:65: error: call of overloaded 'vector(boost::assign_detail::generic_list<int>&)' is ambiguous
| camera_info\_.D = std::vector<double>(list_of(0)(0)(0)(0)(0));
`
Various sources on the internet [1, 2, 3] point to use the
convert_to_container method; hence, this commit follows those
suggestions and with that image_publisher compiles with gcc6.
[1] http://stackoverflow.com/questions/16211410/ambiguity-when-using-boostassignlist-of-to-construct-a-stdvector
[2] http://stackoverflow.com/questions/12352692/ambiguous-call-with-list-of-in-vs2010/12362548#12362548
[3] http://stackoverflow.com/questions/13285272/using-boostassignlist-of?rq=1
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@oss.bmw-carit.de>