external/su: fix terminal support

Change-Id: I2d0c29f256216f24479b5f1051d3d0aeb7e74ac5
su: pts: Fix mismatched return type

the function is declared as an int, always return an int

Change-Id: I90e9815b0fb39d593925f4869455d442f19b0aba
Fix bugreport toast spam.

Change-Id: If6886089aa132694b6aad0a4d3d35646bffbed71
Fix merge derp: Emulated storage should be mounted in the child, not the
parent.

Change-Id: I7bb6e8db1a64de90e96783e07ff26932befe2742
external/su: v1030

Change-Id: If43549a5f08cc3c895977d6a6b1e124dd3ff732b