Oneplus 2 Stuck in boot animation after root
According to this thread on the OnePlus forum:
To return to full stock after a soft brick: 


Download the Fastboot images here (,it restores to OOS 2.1.1)
Extract the zip file to anywhere you'd like
Boot the phone in Fastboot mode (Volume up + power button) 
Connect the phone to the PC
Open the unzipped folder and run the file with the .bat extension (Windows) or a file with name flash-all


The above method doesn't clear the data partition, to clear it: 


Download the userdata.img from here amd flash it using fastboot flash userdata userdata_64.img


And you need a working ADB/Fastboot environment.