typo fix

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/Config.in b/shell/Config.in
index 36a9317..cf599df 100644
--- a/shell/Config.in
+++ b/shell/Config.in
@@ -366,7 +366,7 @@
 
 	  $ exec cttyhack sh
 
-	  Starting an interative shell from boot shell script:
+	  Starting an interactive shell from boot shell script:
 
 	  setsid cttyhack sh