Fix the comments of the rohc_ext_t enum: UO-1-ID packet also handles extensions.
Fix the comments of the rohc_ext_t enum: UO-1-ID packet also handles extensions.

See ticket #896842 entitle "Add extension support for UO-1-ID packet" for details.

didier-barvaux/rohc,didier-barvaux/rohc,didier-barvaux/rohc,didier-barvaux/rohc,didier-barvaux/rohc