core.util: be more resilient when reading command outputs
core.util: be more resilient when reading command outputs

When luarocks.loader runs from within another process,
we may end up getting an Interrupted signal when reading
from a pipe, which is not handled by Lua.

tarantool/luarocks,keplerproject/luarocks,keplerproject/luarocks,luarocks/luarocks,luarocks/luarocks,luarocks/luarocks,keplerproject/luarocks,tarantool/luarocks,keplerproject/luarocks,tarantool/luarocks