load bash profile using --login when running builds on server

load bash profile using --login when running builds on server

This will make `vagrant ssh` and `fdroid build --server` be the same env,
so troubleshooting should be easier.  !135  Here's what `man bash` says:

 When bash is invoked as an interactive login shell, or as a
 non-interactive shell with the --login option, it first reads and
 executes commands from the file /etc/profile, if that file
 exists.  After reading that file, it looks for ~/.bash_profile,
 ~/.bash_login, and ~/.profile, in that order, and reads and
 executes commands from the first one that exists and is readable.
 The --noprofile option may be used when the shell is started to
 inhibit this behavior. When a login shell exits, bash reads and
 executes commands from the file ~/.bash_logout, if it exists.