libcurl: Don't need --without-(ssl/gnutls/nss/mbedtls) twice

libcurl: Don't need --without-(ssl/gnutls/nss/mbedtls) twice

Remove the --without-* options from the yes side of the TLS libraries
selection checks.

Since the --without-* option is now specified when the corresponding TLS
library is not being used, it's no longer necessary when enabling a TLS
library to explicity list all the other TLS libs that curl should not
use.

Signed-off-by: Trent Piepho <tpiepho@impinj.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>