Fix bug in switch_to_fork (shared_from_this() called on object declared on stack)
Fix bug in switch_to_fork (shared_from_this() called on object declared on stack)

(cherry picked from commit 8ea98492070cafb8f8e902f9af6b4e475349a3a4)

Conflicts:
	tests/bitshares_client_tests.cpp

bitshares/bitshares-0.x,FollowMyVote/bitshares,Ziftr/bitshares,bitshares/bitshares,denkhaus/bitsharesx,jakeporter/Bitshares,frrp/bitshares,bitsuperlab/cpp-play,frrp/bitshares,bitshares/devshares,drltc/keyid,drltc/keyid,frrp/bitshares,FollowMyVote/bitshares,FollowMyVote/bitshares,drltc/keyid,dacsunlimited/dac_play,bitshares/devshares,bitshares/bitshares,jakeporter/Bitshares,frrp/bitshares,camponez/bitshares,FollowMyVote/bitshares,jakeporter/Bitshares,bitsuperlab/cpp-play,dacsunlimited/dac_play,bitshares/devshares,FollowMyVote/bitshares,RemitaBit/Remitabit,bitsuperlab/cpp-play,RemitaBit/Remitabit,denkhaus/bitsharesx,Ziftr/bitshares,bitshares/bitshares-0.x,camponez/bitshares,bitshares/devshares,jakeporter/Bitshares,jakeporter/Bitshares,frrp/bitshares,FollowMyVote/bitshares,Ziftr/bitshares,bitshares/devshares,bitshares/bitshares,camponez/bitshares,drltc/keyid,bitshares/devshares,bitshares/bitshares,bitsuperlab/cpp-play,dacsunlimited/dac_play,jakeporter/Bitshares,bitshares/bitshares-0.x,bitsuperlab/cpp-play,dacsunlimited/dac_play,bitshares/bitshares,bitsuperlab/cpp-play,bitshares/bitshares,RemitaBit/Remitabit,RemitaBit/Remitabit,camponez/bitshares,Ziftr/bitshares,camponez/bitshares,frrp/bitshares,dacsunlimited/dac_play,denkhaus/bitsharesx,bitshares/bitshares-0.x,RemitaBit/Remitabit,bitshares/bitshares-0.x,camponez/bitshares,RemitaBit/Remitabit,bitshares/bitshares-0.x,denkhaus/bitsharesx,dacsunlimited/dac_play