Fix building on modern versions of Xcode and OS X.

Recent versions of XCode fail to compile the adb and fastboot binaries due to
two functions being deprecated in 10.9 (GetCurrentProcess and
ProcessInformationCopyDictionary), and the use of -Werrror.

This patch replaces the method implementations which use calls to methods
deprecated in the 10.9 SDK with versions which only call non-deprecated methods.

Change-Id: I855bf26aff45093ca9022924f3ecd1b80f2305a8