[Rummyfan]

In the hey-day of the Britsh Empire, the Brits moved around a lot of workers (usually 'lesser' colonial types) to do the hard labor of the public service projects like the Suez Canal. These were called Workers-on-Government-Service, thus Wogs.

At least that is the explanation I got.

[Prodigal Son]

It doesn't appear that wog is a particularly nice word nor is it an acronym for "worthy oriental gentleman".

Merriam Webster

Main Entry: wog
Pronunciation: 'wäg, 'wog
Function: noun
Etymology: perhaps short for golliwog
Date: circa 1929
chiefly British, usually disparaging : a dark-skinned foreigner; especially : one from the Middle East or Far East

Word Reference.com

wog1 [wɒg]
noun (British) (slang) (derogatory)
a foreigner, esp. one who is not White [ETYMOLOGY: probably from golliwog]

Your Dictionary.com

wog
n. Chiefly British Offensive Slang
Used as a disparaging term for a person of color, especially a person from northern Africa or western or southern Asia.

Dictionary.com- lists a similar definition.

Online Etymology

wog - World War II British armed forces slang for "native of India" (especially as a servant or laborer), possibly shortened from golliwog.

http://rec-puzzles.org/sol.pl/language/english/etymology/acronym

Supposed (but not real) acronyms:

wog Worthy (Wealthy) Oriental Gentleman

American Heritage Dictionary

NOUN: Chiefly British Offensive Slang Used as a disparaging term for a person of color, especially a person from northern Africa or western or southern Asia.
ETYMOLOGY: Probably short for golliwog.

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Which would bring us to golliwog: (again the American Heritage Dictionary)

NOUN: A doll fashioned in grotesque caricature of a Black male.
ETYMOLOGY: After Golliwog, a character in books by Florence Upton (died 1922), American illustrator.

Some more info on the etymology of the word wog and offered by Oxford's

http://acadprojwww.wlu.edu/vol4/BlackmerH/public_html/xliberty/oed/wogcite.html