buildconf/coverity: drop gccgo as it does not compile with modern gcc

buildconf/coverity.ini

@@ -1,3 +1,3 @@
 [uwsgi]
-main_plugin = psgi,rack,lua,python,gevent,php,cgi,gccgo,glusterfs,pty,xslt,msgpack,geoip,v8,pam,ldap,mono,jvm,ring,jwsgi,servlet,rados,coroae,pypy,airbrake,alarm_curl,alarm_xmpp,asyncio,cheaper_backlog2,clock_monotonic,clock_realtime,cplusplus,curl_cron,dumbloop,dummy,echo,emperor_amqp,emperor_pg,emperor_zeromq,example,exception_log,fiber,forkptyrouter,graylog2,legion_cache_fetch,libffi,logcrypto,libtcc,logpipe,logzmq,matheval,notfound,pyuwsgi,rbthreads,router_access,router_radius,router_spnego,router_xmldir,sqlite3,ssi,stats_pusher_file,stats_pusher_statsd,systemd_logger,tornado,transformation_toupper,tuntap,webdav,xattr,zabbix
+main_plugin = psgi,rack,lua,python,gevent,php,cgi,glusterfs,pty,xslt,msgpack,geoip,v8,pam,ldap,mono,jvm,ring,jwsgi,servlet,rados,coroae,pypy,airbrake,alarm_curl,alarm_xmpp,asyncio,cheaper_backlog2,clock_monotonic,clock_realtime,cplusplus,curl_cron,dumbloop,dummy,echo,emperor_amqp,emperor_pg,emperor_zeromq,example,exception_log,fiber,forkptyrouter,graylog2,legion_cache_fetch,libffi,logcrypto,libtcc,logpipe,logzmq,matheval,notfound,pyuwsgi,rbthreads,router_access,router_radius,router_spnego,router_xmldir,sqlite3,ssi,stats_pusher_file,stats_pusher_statsd,systemd_logger,tornado,transformation_toupper,tuntap,webdav,xattr,zabbix
 inherit = base