Always use clang for iotop.

iotop makes use of a lambda that uses an `auto` typedef parameter.
This is a C++14 feature, and we need to move GCC back to C++11 because
GCC 4.9 doesn't have a correct C++14 ABI.

Bug: http://b/25022512
Change-Id: I3946bd3d287c99eeee1d570ea46e073828b5c1d2
1 file changed