BuildSystem: Check for header file of OGG.

Asterisk uses various symbols of the shared library libogg within the module
format_ogg_vorbis. However, the source code of that module did not include the
header file of libogg explicitly but implicitly. Because that header was not
included before Asterisk 14, the script ./configure was told not to check for
it.

Anyway, even Asterisk 13 LTS uses symbols of libogg. Therefore, that header
should be included explicitly. Therefore, ./configure should check for that
header.

Change-Id: I98c50d56311b68880d1084fcc62c35ab2f8692db