Fix connection-closed error when passing bad headers
Fix connection-closed error when passing bad headers

Parsing version or uname could possibly result in a newline character
which is rejected in a fantastically silent fashion by the server.
This trims any whitespace when constructing the user agent header in
`habitat_http_client::api_client`

Signed-off-by: Jamie Winsor <b4dde37aa2aac745c0e6c43447507eaeace3e59f@vialstudios.com>

rsertelon/habitat,habitat-sh/habitat,habitat-sh/habitat,habitat-sh/habitat,habitat-sh/habitat,rsertelon/habitat,rsertelon/habitat,habitat-sh/habitat,rsertelon/habitat,rsertelon/habitat,habitat-sh/habitat,habitat-sh/habitat,rsertelon/habitat,rsertelon/habitat,habitat-sh/habitat