Remove reference to gdbserver

gdbserver was removed by I63ee74b4fbdedaa5082d2dbbb21909771caa24c1.

Test: treehugger
Change-Id: I141ea100af8c2148d60930c808f0e760857e15aa
diff --git a/tools/buildbot-build.sh b/tools/buildbot-build.sh
index 7798997..4d38dcf 100755
--- a/tools/buildbot-build.sh
+++ b/tools/buildbot-build.sh
@@ -109,7 +109,7 @@
   fi
   make_command+=" build-art-target-tests"
   make_command+=" libnetd_client-target toybox sh libtombstoned_client"
-  make_command+=" debuggerd su gdbserver"
+  make_command+=" debuggerd su"
   # vogar requires the class files for conscrypt and ICU.
   make_command+=" conscrypt core-icu4j"
   make_command+=" ${ANDROID_PRODUCT_OUT#"${ANDROID_BUILD_TOP}/"}/system/etc/public.libraries.txt"