install-aws-server: Fix shellcheck warnings.
install-aws-server: Fix shellcheck warnings.

In tools/setup/install-aws-server line 25:
zulip_root=${ZULIP_ROOT:-$HOME/zulip}
^-- SC2034: zulip_root appears unused. Verify use (or export if used externally).

In tools/setup/install-aws-server line 40:
if [ -n "$zulip_confdir" ]; then
         ^-- SC2154: zulip_confdir is referenced but not assigned.

In tools/setup/install-aws-server line 55:
VIRTUALENV_NEEDED=$(if $(echo "$type" | grep -q app_frontend); then echo -n yes; else echo -n no; fi)
                       ^-- SC2091: Remove surrounding $() to avoid executing output.

In tools/setup/install-aws-server line 60:
SSH_OPTS=(-o HostKeyAlgorithms=ssh-rsa)
             ^-- SC2191: The = here is literal. To assign by index, use ( [index]=value ) with no spaces. To keep as literal, quote it.

In tools/setup/install-aws-server line 69:
ssh "${SSH_OPTS[@]}" "$server" -t -i "$amazon_key_file" -lroot <<EOF
                                                                 ^-- SC2087: Quote 'EOF' to make here document expansions happen on the server side rather than on the client.

In tools/setup/install-aws-server line 86:
ssh "${SSH_OPTS[@]}" "$server" -t -i "$amazon_key_file" -lroot <<EOF
                                                                 ^-- SC2087: Quote 'EOF' to make here document expansions happen on the server side rather than on the client.

Signed-off-by: Anders Kaseorg <087231934ba8fcf78bc142ce37d193b895ac03c4@mit.edu>

timabbott/zulip,rishig/zulip,brainwane/zulip,andersk/zulip,shubhamdhama/zulip,rishig/zulip,zulip/zulip,tommyip/zulip,eeshangarg/zulip,andersk/zulip,brainwane/zulip,jackrzhang/zulip,andersk/zulip,zulip/zulip,tommyip/zulip,punchagan/zulip,punchagan/zulip,brainwane/zulip,hackerkid/zulip,shubhamdhama/zulip,timabbott/zulip,dhcrzf/zulip,eeshangarg/zulip,jackrzhang/zulip,synicalsyntax/zulip,rht/zulip,synicalsyntax/zulip,zulip/zulip,shubhamdhama/zulip,hackerkid/zulip,timabbott/zulip,showell/zulip,dhcrzf/zulip,rht/zulip,andersk/zulip,hackerkid/zulip,rht/zulip,tommyip/zulip,showell/zulip,rishig/zulip,zulip/zulip,rht/zulip,dhcrzf/zulip,andersk/zulip,rht/zulip,kou/zulip,showell/zulip,brainwane/zulip,brainwane/zulip,punchagan/zulip,rishig/zulip,kou/zulip,shubhamdhama/zulip,punchagan/zulip,rishig/zulip,zulip/zulip,kou/zulip,eeshangarg/zulip,kou/zulip,hackerkid/zulip,synicalsyntax/zulip,andersk/zulip,shubhamdhama/zulip,showell/zulip,eeshangarg/zulip,brainwane/zulip,eeshangarg/zulip,brainwane/zulip,kou/zulip,dhcrzf/zulip,showell/zulip,zulip/zulip,showell/zulip,synicalsyntax/zulip,punchagan/zulip,jackrzhang/zulip,synicalsyntax/zulip,kou/zulip,shubhamdhama/zulip,showell/zulip,jackrzhang/zulip,timabbott/zulip,punchagan/zulip,synicalsyntax/zulip,kou/zulip,tommyip/zulip,andersk/zulip,hackerkid/zulip,jackrzhang/zulip,rht/zulip,tommyip/zulip,rishig/zulip,eeshangarg/zulip,timabbott/zulip,rht/zulip,dhcrzf/zulip,tommyip/zulip,jackrzhang/zulip,dhcrzf/zulip,dhcrzf/zulip,timabbott/zulip,jackrzhang/zulip,eeshangarg/zulip,tommyip/zulip,synicalsyntax/zulip,hackerkid/zulip,shubhamdhama/zulip,rishig/zulip,punchagan/zulip,hackerkid/zulip,timabbott/zulip,zulip/zulip