condition: allow literal string compares in SMBIOS condition

This ensures that "=" and "!=" are now interpreted as literal string
compares, and "==" and "<>" are for version compares.

This is not a compat break, since the SMBIOS stuff has not been included
in any release yet.

Main reason to do this, is to be systematic with the other conditions
that check for text stuff.

src/shared/condition.c

@@ -528,7 +528,7 @@ static int condition_test_firmware_smbios_field(const char *expression) {
         delete_trailing_chars(field, WHITESPACE);
 
         /* Parse operator */
-        operator = parse_compare_operator(&expression, COMPARE_ALLOW_FNMATCH);
+        operator = parse_compare_operator(&expression, COMPARE_ALLOW_FNMATCH|COMPARE_EQUAL_BY_STRING);
         if (operator < 0)
                 return operator;