This is caused by a conflict between libetpan-dev which requires libcurl4-gnutls-dev and libgdata-dev which requires (via liboauth-dev) libcurl4-nss-dev. Those two libcurl packages both satisfy the libcurl-dev dependency, but conflict. I can't think of a resolution short of disabling one of the plugins - but which one?
This is caused by a conflict between libetpan-dev which requires libcurl4-gnutls-dev and libgdata-dev which requires (via liboauth-dev) libcurl4-nss-dev. Those two libcurl packages both satisfy the libcurl-dev dependency, but conflict. I can't think of a resolution short of disabling one of the plugins - but which one?