Let's take a look at how it's rendered in the Greek (John 1:1 Greek New Testament):
"᾿Εν ἀρχῇ ἦν ὁ Λόγος, καὶ ὁ Λόγος ἦν πρὸς τὸν Θεόν, καὶ Θεὸς ἦν ὁ Λόγος."
How was the phrase "God was the Word" rendered in Greek? "Θεὸς ἦν ὁ Λόγος" (Theos ēn ho Logos). Notice that the word Theos is without the article ho.
What is the difference between Theos and ho Theos? (Hermeneia – A Critical and Historical Commentary of the Bible, by Ernst Haenchen, p. 109)
"In order to avoid misunderstanding, it may be asserted here that Theos and ho Theos ('god, divine' and 'the God') were not the same thing in this period. Philo has therefore written: 'The Logos means only Theos (‘divine’) and not ho Theos (‘God’) since the logos is not God in the strict sense.” Philo was not thinking of giving up Jewish monotheism. In a similar fashion, Origen, too, interprets: 'The Evangelist does not say that the logos is ‘God,’ but only that the logos is ‘divine.’' In fact, for the author of the hymn, as for the Evangelist, only the Father was 'God' (ho Theos; cf. 17:3); 'the Son' was subordinate to him (cf. 14:28)."
What does Theos without the article ho mean in this instance? "divine". Hence, the rendering "the Logos was divine" is correct.