Remove unnecessary 'global' keyword uses

[tonypr]

The global keyword should be used when the variable in question is being assigned to as otherwise it would create a local variable as opposed to operating on the global variable.

I.e.

global STATIC_GRAPH
STATIC_GRAPH = new_graph()

This PR removes uses of global in cases where the variable is only being accessed and not assigned to.

[netlify[bot]]

✅ Deploy Preview for catanatron-staging canceled.

Name	Link
🔨 Latest commit	ac83aafb3fb25498ded6e60b354698b162d50eec
🔍 Latest deploy log	https://app.netlify.com/sites/catanatron-staging/deploys/63478b9cd0761c000864f8af

[coveralls]

Pull Request Test Coverage Report for Build 3239546120

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 95.798%

---

Totals
Change from base Build 3077671355:	0.0%
Covered Lines:	1368
Relevant Lines:	1428

---

💛 - Coveralls

[bcollazo]

LGTM! Thanks!