Fix rcutils_shared_library_t path on Windows. (ros2#322)

GetModuleFileName() returns the size of the filename *minus* the null-terminating character.

Signed-off-by: Michel Hidalgo <michel@ekumenlabs.com>

src/shared_library.c

@@ -177,7 +177,7 @@ rcutils_load_shared_library(
       continue;
     }
     lib->library_path = lib->allocator.reallocate(
-      buffer, buffer_size, lib->allocator.state);
+      buffer, buffer_size + 1, lib->allocator.state);
     if (NULL == lib->library_path) {
       lib->library_path = buffer;
     }