Drop compatibility with pre 2012 adb clients

On very old versions of adb, when "adb bugreport" was executed,
the command "adb shell dumpstate" was run. This was later changed
to "adb shell bugreport". Change
1e339878c128ef47271278779c2685a8dfa49cd1 added a backwards
compatibility hack (see bug 6391938).

It turns out that nobody has been able to execute
/system/bin/dumpstate as a non-root user for 2 releases now due
to SELinux restrictions, so maintaining the code bloat to support
this workaround is pointless.

Delete the code.

Bug: 6391938
Change-Id: I49eebcca1fcec5a39593c53e2e6d23ec87f65a35
diff --git a/cmds/dumpstate/dumpstate.cpp b/cmds/dumpstate/dumpstate.cpp
index af95d16..f207bb5 100644
--- a/cmds/dumpstate/dumpstate.cpp
+++ b/cmds/dumpstate/dumpstate.cpp
@@ -1025,15 +1025,6 @@
 
     now = time(NULL);
 
-    if (getuid() != 0) {
-        // Old versions of the adb client would call the
-        // dumpstate command directly. Newer clients
-        // call /system/bin/bugreport instead. If we detect
-        // we're being called incorrectly, then exec the
-        // correct program.
-        return execl("/system/bin/bugreport", "/system/bin/bugreport", NULL);
-    }
-
     MYLOGI("begin\n");
 
     /* gets the sequential id */