build: remove a header defined twice
Fixes the following warning:
src/libnm-client-impl/meson.build:139: WARNING: Keyword argument "header" defined multiple times. WARNING: This will be an error in future Meson releases.
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Fixes the following warning:
src/libnm-client-impl/meson.build:139: WARNING: Keyword argument "header" defined multiple times. WARNING: This will be an error in future Meson releases.