Invalid template passed to ipfs object new [<template>] causes a sigsegv

[achingbrain]

Version information:

go-ipfs version: 0.7.0
Repo version: 10
System version: amd64/darwin
Golang version: go1.14.4

Description:

Running ipfs object new and not passing unixfs-dir as the template causes a big stack trace instead of just printing an error message:

$ ipfs object new hello
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x18 pc=0x15107a7]

goroutine 1 [running]:
github.com/ipfs/go-blockservice.(*blockService).AddBlock(0xc000de3470, 0x0, 0x0, 0x0, 0x0)
	github.com/ipfs/[email protected]/blockservice.go:134 +0x37
github.com/ipfs/go-merkledag.(*dagService).Add(0xc0000e1410, 0x25d4840, 0xc0008328c0, 0x0, 0x0, 0x0, 0xc00095da90)
	github.com/ipfs/[email protected]/merkledag.go:51 +0x8c
github.com/ipfs/go-ipfs/core/coreapi.(*ObjectAPI).New(0xc0008a1b80, 0x25d4840, 0xc0008328c0, 0xc0001164a8, 0x1, 0x1, 0x0, 0xc000112fd0, 0x1a, 0x2191a26)
	github.com/ipfs/[email protected]/core/coreapi/object.go:53 +0xd3
github.com/ipfs/go-ipfs/core/commands/object.glob..func8(0xc0002ae000, 0x25d4cc0, 0xc0007808a0, 0x2023380, 0xc0007807e0, 0xc00091fc40, 0x1df067e)
	github.com/ipfs/[email protected]/core/commands/object/object.go:502 +0x1bf
github.com/ipfs/go-ipfs-cmds.(*executor).Execute(0xc0001809e8, 0xc0002ae000, 0x25d4cc0, 0xc0007808a0, 0x2023380, 0xc0007807e0, 0xc0007808a0, 0x0)
	github.com/ipfs/[email protected]/executor.go:77 +0x171
github.com/ipfs/go-ipfs-cmds/cli.Run(0x25d4840, 0xc0007fc940, 0x331be00, 0xc000186040, 0x4, 0x4, 0xc000180000, 0xc000180008, 0xc000180010, 0x23f4970, ...)
	github.com/ipfs/[email protected]/cli/run.go:137 +0xa72
main.mainRet(0x0)
	github.com/ipfs/[email protected]/cmd/ipfs/main.go:168 +0x451
main.main()
	github.com/ipfs/[email protected]/cmd/ipfs/main.go:71 +0x22