Update lldb to track recent Triple arm64 enum removal and collapse into aarch64.

See the following llvm change for details:

r213743 | tnorthover | 2014-07-23 05:32:47 -0700 (Wed, 23 Jul 2014) | 9 lines
AArch64: remove arm64 triple enumerator.

This change fixes build breaks on Linux and MacOSX lldb.

llvm-svn: 213755
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
index 9898cb9..9bc0a96 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
@@ -1748,7 +1748,7 @@
                             {
                                 switch (m_host_arch.GetMachine())
                                 {
-                                case llvm::Triple::arm64:
+                                case llvm::Triple::aarch64:
                                 case llvm::Triple::arm:
                                 case llvm::Triple::thumb:
                                     os_name = "ios";
@@ -1789,7 +1789,7 @@
                         {
                             switch (m_host_arch.GetMachine())
                             {
-                                case llvm::Triple::arm64:
+                                case llvm::Triple::aarch64:
                                 case llvm::Triple::arm:
                                 case llvm::Triple::thumb:
                                     host_triple.setOS(llvm::Triple::IOS);
@@ -3466,7 +3466,7 @@
             if (arch.IsValid()
                 && arch.GetTriple().getVendor() == llvm::Triple::Apple
                 && arch.GetTriple().getOS() == llvm::Triple::IOS
-                && arch.GetTriple().getArch() == llvm::Triple::arm64)
+                && arch.GetTriple().getArch() == llvm::Triple::aarch64)
             {
                 m_avoid_g_packets = eLazyBoolYes;
                 uint32_t gdb_server_version = GetGDBServerProgramVersion();