libcurl: drop polarssl support

As of curl 7.36.0 it doesn't support polarssl < 1.3 any longer. Fixes:
http://autobuild.buildroot.net/results/d82/d82c3618e9dde3da7e36ba2b58545a9a8de5e442/

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/libcurl/libcurl.mk

@@ -36,9 +36,6 @@ LIBCURL_CONF_OPT += --with-ssl=$(STAGING_DIR)/usr \
 else ifeq ($(BR2_PACKAGE_GNUTLS),y)
 LIBCURL_CONF_OPT += --with-gnutls=$(STAGING_DIR)/usr
 LIBCURL_DEPENDENCIES += gnutls
-else ifeq ($(BR2_PACKAGE_POLARSSL),y)
-LIBCURL_CONF_OPT += --with-polarssl=$(STAGING_DIR)/usr
-LIBCURL_DEPENDENCIES += polarssl
 else ifeq ($(BR2_PACKAGE_LIBNSS),y)
 LIBCURL_CONF_OPT += --with-nss=$(STAGING_DIR)/usr
 LIBCURL_CONF_ENV += CPPFLAGS="$(TARGET_CPPFLAGS) `$(PKG_CONFIG_HOST_BINARY) nspr nss --cflags`"