[Cogl] [Patch][Cogl-1.18]: Update cogl.symbols and cogl-path.symbols

[Fan Chun-wei]

Hi,

In the course of Lionel's work to support Cogl better for introspection, 
a number of public symbols were added, so this patch updates 
cogl.symbols and cogl-path.symbols so that these symbols can be properly 
exported.  This fixes the build of the conformance test program, and 
also allows the introspection to build and link properly.

With blessings, thank you!