Merge branch 'xx/remote-server-option-config'

A new configuration variable remote.<name>.serverOption makes the transport layer act as if the --serverOption=<value> option is given from the command line. * xx/remote-server-option-config: ls-remote: leakfix for not clearing server_options fetch: respect --server-option when fetching multiple remotes transport.c::handshake: make use of server options from remote remote: introduce remote.<name>.serverOption configuration transport: introduce parse_transport_option() method