Bottles are created for Yosemite and higher

After Issue #985 was merged, bottles for Mavericks are no longer
being built, meaning installations are triggering builds.

Update the FAQ to show that builds will most likely now be
triggers on Mavericks since their bottles are not being generated.

docs/FAQ.md

@@ -96,8 +96,8 @@ will use a bottled version of $FORMULA, but
 `brew install $FORMULA --enable-bar` will trigger a source build.
 * The `--build-from-source` option is invoked.
 * The environment variable `HOMEBREW_BUILD_FROM_SOURCE` is set.
-* The machine is not running OS X 10.9+ as all bottled builds are
-generated on Mavericks or later.
+* The machine is not running OS X 10.10+ as all bottled builds are
+generated on Yosemite or later.
 * Homebrew is installed to a prefix other than the standard
 `/usr/local` (although some bottles support this)