Remove dead code from debuggerd.

  system/core/debuggerd/debuggerd.cpp:683:5: warning: Value stored to 'logsocket' is never read
    logsocket = -1;
    ^           ~~

Bug: http://b/27264392
Change-Id: I8eab8a02b67f219c32aea49e4d4957e5642df38f