This patch addresses a bug reported at llvm.org
http://llvm.org/bugs/show_bug.cgi?id=11809

The Mac clang compiler can generate coverage information. But when the
executables run, they place the .gcda files in the wrong
directories. The .gcda files should be in the same directory as the
.gcno files. This patch adds a python script fixcoverage.py that moves
each .gcda file into the directory containing the associated .gcno
file.

Change-Id: If0d12a3834b3649a41230ad131a8625c9b61481b