Tesla shares plunged more than 9% at the cash open on Thursday after CEO Elon Musk lamented the company faced some 'rough quarters' ahead on its Q2 earnings call Wednesday evening. Here is what Tesla reported for Q2: Adjusted EPS 40c vs. 52c y/y, missing estimate 42c (GAAP EPS 33c vs. 42c y/y). According to Bloomberg "investors may be relived it reported adjusted EPS just 2 cents below Wall Street estimates" Revenue $22.50 billion, -12% y/y, missing estimates of $22.64 billion Gross margin 17.2% vs. 18% y/y, beating estimates…