mbed detect doesn't work on Mac OoB RC#1

[bulislaw]

Version: https://github.com/mbedmicro/mbed/releases/tag/mbed-os-5.1.0-rc1
Target: K64F/Giant Gecko/Pearl Gecko/NUCLEO_L476RG/nRF51_DK
Host OS: Mac

mbed can't detect connected boards making mbed test fail

$ mbed detect 
[mbed] No mbed targets where detected on your system.

[bulislaw]

Know issue: ARMmbed/mbed-ls#38