Use accept instead of accept4 for Android.

Summary:
The accept4 syscall is missing on older ARM Android kernels, and the accept()
call is implemented with the accept4 syscall, so we'll need to call the accept
syscall directly.

Reviewers: vharron, tberghammer, labath

Subscribers: ovyalov, chaoren, labath, tberghammer, aemerson, lldb-commits

Differential Revision: http://reviews.llvm.org/D10887

llvm-svn: 242319