[epiphany] profile-migrator: Don't crash when passed invalid -d

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 974d8332e0de1e43aa85fc16d39deb2b8ce33ecd
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Wed Feb 1 12:31:01 2017 -0600

    profile-migrator: Don't crash when passed invalid -d

 src/profile-migrator/ephy-profile-migrator.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/src/profile-migrator/ephy-profile-migrator.c b/src/profile-migrator/ephy-profile-migrator.c
index 990b781..fbb224c 100644
--- a/src/profile-migrator/ephy-profile-migrator.c
+++ b/src/profile-migrator/ephy-profile-migrator.c
@@ -839,6 +839,8 @@ ephy_migrator (void)
   int latest, i;
   EphyProfileMigrator m;
 
+  g_assert (EPHY_PROFILE_MIGRATION_VERSION == G_N_ELEMENTS (migrators));
+
   /* Always try to migrate the data from the old profile dir at the
    * very beginning. */
   migrate_profile_gnome2_to_xdg ();
@@ -853,6 +855,11 @@ ephy_migrator (void)
     if (do_step_n >= EPHY_PROFILE_MIGRATION_VERSION)
       return FALSE;
 
+    if (do_step_n < 1) {
+      g_printf ("Invalid migration step %d\n", do_step_n);
+      return FALSE;
+    }
+
     LOG ("Running only migrator: %d", do_step_n);
     m = migrators[do_step_n - 1];
     m ();