camo: Extract generate_camo_url out from get_camo_url.
camo: Extract generate_camo_url out from get_camo_url.

This will help us eliminate camo from our production installs.
Basically it helps us de duplicate some code from upcoming code
which will help us check validity of a camo url.

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