cmd/go: add missing newline at end of error message
cmd/go: add missing newline at end of error message

Change-Id: I9277e869e171d9e051ff9a70ac578b8127fa74f8
Reviewed-on: https://go-review.googlesource.com/33897
Run-TryBot: Josh Bleecher Snyder <cdc248cc4d32e4fbfe04e45228163bcecd48a0b9@gmail.com>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

Cofyc/go,nawawi/go,goodlang/good,linux-on-ibm-z/go,suncycheng/go,goodlang/good,Cofyc/go,ImJasonH/go,linux-on-ibm-z/go,golang/go,codestation/go,CAFxX/go,josharian/go,vsekhar/elastic-go,akutz/go,derekmarcotte/go,goodlang/good,CAFxX/go,akutz/go,suncycheng/go,polyverse-security/go,codestation/go,Cofyc/go,codestation/go,linux-on-ibm-z/go,ImJasonH/go,vsekhar/elastic-go,josharian/go,goodlang/good,Cofyc/go,nawawi/go,akutz/go,golang/go,codestation/go,vsekhar/elastic-go,vsekhar/elastic-go,derekmarcotte/go,CAFxX/go,ImJasonH/go,goodlang/good,vsekhar/elastic-go,goodlang/good,josharian/go,Cofyc/go,CAFxX/go,suncycheng/go,josharian/go,josharian/go,linux-on-ibm-z/go,cloudflare/go,nawawi/go,polyverse-security/go,CAFxX/go,josharian/go,suncycheng/go,derekmarcotte/go,golang/go,ImJasonH/go,cloudflare/go,cloudflare/go,codestation/go,Cofyc/go,goodlang/good,akutz/go,polyverse-security/go,derekmarcotte/go,polyverse-security/go,linux-on-ibm-z/go,vsekhar/elastic-go,golang/go,suncycheng/go,ImJasonH/go,derekmarcotte/go,ImJasonH/go,ImJasonH/go,linux-on-ibm-z/go,derekmarcotte/go,derekmarcotte/go,polyverse-security/go,nawawi/go,linux-on-ibm-z/go,ImJasonH/go,Cofyc/go,suncycheng/go,cloudflare/go,golang/go,cloudflare/go,polyverse-security/go,polyverse-security/go,josharian/go,golang/go,akutz/go,nawawi/go,josharian/go,nawawi/go,nawawi/go,codestation/go,CAFxX/go,polyverse-security/go,christopher-henderson/Go,cloudflare/go,nawawi/go,suncycheng/go,cloudflare/go,akutz/go,suncycheng/go,goodlang/good,CAFxX/go,derekmarcotte/go,vsekhar/elastic-go,Cofyc/go,CAFxX/go,linux-on-ibm-z/go,golang/go,codestation/go,akutz/go,akutz/go,vsekhar/elastic-go,cloudflare/go,codestation/go,golang/go