apibuild: Simplify conditional statements

apibuild: Simplify conditional statements

Improve readability by reducing the complexity and length of
conditional statements.

Example: The following condition:

	if (o >= 97 and o <= 122) or
	   (o >= 65 and o <= 90) or
	   (o >= 48 and o <= 57) or
	   (" \t(){}:;,+-*/%&!|[]=><".find(line[i]) == -1):

Will be True for every character that is not in string:
	" \t(){}:;,+-*/%&!|[]=><"

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Radostin Stoyanov <rstoyanov1@gmail.com>