bug 1085557 - Add Socorro symbol upload token file to linux mozconfigs. r=coop

--HG--
extra : rebase_source : d30d0cd32c99de4a2b24896094eeca33aa203ba8

build/unix/mozconfig.linux

@@ -41,3 +41,5 @@ if [ -d "$topsrcdir/gtk3" ]; then
   mk_add_options "export LD_LIBRARY_PATH=$topsrcdir/gtk3/usr/local/lib"
   ac_add_options --enable-default-toolkit=cairo-gtk3
 fi
+
+export SOCORRO_SYMBOL_UPLOAD_TOKEN_FILE=/builds/crash-stats-api.token