NetworkCapabilities: remove duplicated TRANSPORT_NAMES

Due to multi-branch automerging issue, TRANSPORT_NAMES got inserted
twice into NetworkCapabilities both by commits a365bace and
9910dbc6. This patch deletes one of the copy.

Test: no functionality change. Build is fixed.
Change-Id: I2adec1a9cb1ee6f1d61dfeec2d0b92b8141eed88