loader: set PT_INTERP to itself

Some versions of kernel set AT_BASE to 0
if dynamic loader does not have PT_INTERP
set.

Bug: http://b/30739481
Test: run /system/bin/linker64 and /system/bin/linker
Change-Id: I1b67777166fe917d3ee1a97277045ca6f5db0084
diff --git a/linker/linker_main.cpp b/linker/linker_main.cpp
index d52b1d6..d037a18 100644
--- a/linker/linker_main.cpp
+++ b/linker/linker_main.cpp
@@ -496,7 +496,7 @@
   // see also https://code.google.com/p/android/issues/detail?id=63174
   if (reinterpret_cast<ElfW(Addr)>(&_start) == entry_point) {
     __libc_format_fd(STDOUT_FILENO,
-                     "This is %s, the helper program for shared library executables.\n",
+                     "This is %s, the helper program for dynamic executables.\n",
                      args.argv[0]);
     exit(0);
   }