pidgin/pidgin

Remove the log reader plugin now that the History API has landed.

At some point we can come back and integrate this code into purple-history but
right now it's just dead weight.

Testing Done:
Compiled and ran and verified there were no issues.

Reviewed at https://reviews.imfreedom.org/r/1036/
nullclient = executable('nullclient', 'nullclient.c', 'defines.h',
c_args : ['-DSTANDALONE'],
dependencies : [libpurple_dep, glib])