fuchsia: Fix compile of base/logging.cc
fuchsia: Fix compile of base/logging.cc

Now that things are actually compiling mostly correctly, the MX/ZX
errors are more obvious. Fix this simple one in logging.cc.

Bug: crashpad:196
Change-Id: I005b74c6136f6a1dba10c70f2d03d92884fd2c86
Reviewed-on: https://chromium-review.googlesource.com/786818
Reviewed-by: Mark Mentovai <f1b5a91d4d6ad523f2610114591c007e75d15084@chromium.org>

chromium/mini_chromium,chromium/mini_chromium,chromium/mini_chromium