Bump CoreFX to pickup the fix for #14214. (#14821)

Martin Baulig · marek-safar · commit c6edaa62f94b · 2019-06-06T09:33:02.000+02:00
HttpClient.SendAsync() should not attempt to read response body on a HEAD request. * CoreFX PR dotnet/corefx#38129. * Backported in mono/corefx#297. * Fixes #14214. (cherry picked from commit 2b3a23c)
diff --git a/external/corefx b/external/corefx
@@ -1 +1 @@
-Subproject commit 6f6e62c4ed51587f7601ad05423561ee4e01eb99
+Subproject commit cb2c46b3f2b0097ea4ccb71de296b7760eeda26e
