Spanish towerco Cellnex, which had been famous for its rapacious appetite for European infrastructure assets, is continuing its Europe-wide asset sales to pay off debt and spiff up its reputation among investors to an ‘investment grade’ standard. The latest chapter in Cellnex’s retrenchment story are rumors that it will sell a minority stake in its operations in Poland. The deal would value Cellnex’s Polish unit at around €3 billion, and though the details of this deal are vague, Cellnex is on a very clear path to reduce debt and sell assets. Cellnex owns and operates more than 100,000 wireless towers in Europe, acquired in six years of unrelenting M&A activity since its initial public offering in 2015. But the times…