Move select buildpack login into own function
Move select buildpack login into own function

Signed-off-by: Dmitriy Zaporozhets <be23d75b156792e5acab51b196a2deb155d35d6a@gmail.com>

gliderlabs/herokuish,expa/herokuish,expa/herokuish,expa/herokuish,expa/herokuish,gliderlabs/herokuish,gliderlabs/herokuish,expa/herokuish,gliderlabs/herokuish,expa/herokuish,gliderlabs/herokuish,expa/herokuish,gliderlabs/herokuish,expa/herokuish,gliderlabs/herokuish,gliderlabs/herokuish