Bump libsrtp version 368abd6bb3 -> 650611720e.

Not a real change to libsrtp itself but just a rename of
//third_party/libsrtp/VERSION to //third_party/libsrtp/LIBSRTP_VERSION
in order to avoid issues with libc++.

Bug: 883897
Change-Id: Iccd0dcc5ee1e3e9339ecbf96f3b6d7844d8fc135
Reviewed-on: https://chromium-review.googlesource.com/1225873
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#591323}

DEPS

@@ -833,7 +833,7 @@ deps = {
     Var('chromium_git') + '/external/github.com/google/libprotobuf-mutator.git' + '@' +  Var('libprotobuf-mutator'),
 
   'src/third_party/libsrtp':
-    Var('chromium_git') + '/chromium/deps/libsrtp.git' + '@' + '368abd6bb3091df2b354250818714f72f0692ca5',
+    Var('chromium_git') + '/chromium/deps/libsrtp.git' + '@' + '650611720ecc23e0e6b32b0e3100f8b4df91696c',
 
   # Android Explicit Synchronization.
   'src/third_party/libsync/src': {