capability: fix string comparison in cap_name_to_number

The result of strcasecmp was being used incorrectly.  This function
returns 0 if the strings match.

Signed-off-by: Mark Marshall <mark.marshall@omicronenergy.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

libbb/capability.c

@@ -67,7 +67,7 @@ unsigned FAST_FUNC cap_name_to_number(const char *cap)
 		goto found;
 	}
 	for (i = 0; i < ARRAY_SIZE(capabilities); i++) {
-		if (strcasecmp(capabilities[i], cap) != 0)
+		if (strcasecmp(capabilities[i], cap) == 0)
 			goto found;
 	}
 	bb_error_msg_and_die("unknown capability '%s'", cap);