test-lib-functions: adjust style to match CodingGuidelines
test-lib-functions: adjust style to match CodingGuidelines

Prefer "test" over "[ ]" for conditionals.
Prefer "$()" over backticks for command substitutions.
Avoid control structures on a single line with semicolons.

Signed-off-by: David Aguilar <9de348c050f7cd1ca590883733c4e531ce610bf4@gmail.com>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git