Resolves: bug 458171

Description: approx search accidentally fails with timelimit although it hasn't hit timelimit.
Fix Description: string_filter_approx used to simply return the return value from
strcmp.  The value could be evaluated as LDAP RETURN CODE.
string_filter_approx is a static function and it's called only from
string_filter_ava.  The function returns -1 when it fails. Thus, adjusting the
return value of string_filter_approx to the caller function.

ldap/servers/plugins/syntaxes/string.c

@@ -114,6 +114,10 @@ string_filter_ava( struct berval *bvfilter, Slapi_Value **bvals, int syntax,
 	return( -1 );
 }
 
+/*
+ * return value:  0 -- approximately matched
+ *               -1 -- did not match
+ */
 static int
 string_filter_approx( struct berval *bvfilter, Slapi_Value **bvals,
 							 Slapi_Value **retVal)
@@ -181,6 +185,9 @@ string_filter_approx( struct berval *bvfilter, Slapi_Value **bvals,
 			break;
 		}
 	}
+	if (0 != rc) {
+		rc = -1;
+	}
 	LDAPDebug( LDAP_DEBUG_TRACE, "<= string_filter_approx %d\n",
 	    rc, 0, 0 );