Fix Exasol and Firebird test errors

Plug a few more holes in the expectation that Sqitch always raises
App::Sqitch::X objects rather than strings, as discovered by some
unanticipated test configurations (resolves #858). Also fix a couple of
typos and the default URI for Exasol tests.

Changes

@@ -1,6 +1,6 @@
 Revision history for Perl extension App::Sqitch
 
-1.5.1  Note yet released
+1.5.1  Not yet released
 
 1.5.0  2025-01-08T03:22:40
      - Fix improperly nested Pod headers that were incrementing two levels

t/exasol.t

@@ -414,7 +414,7 @@ END {
 $uri = URI->new(
     $ENV{SQITCH_TEST_EXASOL_URI} ||
     $ENV{EXA_URI} ||
-    'db:dbadmin:password@localhost/dbadmin'
+    'db:exasol://dbadmin:password@localhost/dbadmin'
 );
 my $err;
 for my $i (1..30) {

t/firebird.t

@@ -31,7 +31,7 @@ my $uri;
 my $tmpdir;
 my $have_fb_driver = 1; # assume DBD::Firebird is installed and so is Firebird
 
-# Is DBD::Firebird realy installed?
+# Is DBD::Firebird really installed?
 try { require DBD::Firebird; } catch { $have_fb_driver = 0; };
 
 BEGIN {
@@ -472,11 +472,13 @@ DBIEngineTest->run(
         # DBD::Firebird.
         my $cmd = $self->client;
         my $cmd_echo = qx(echo "quit;" | "$cmd" -z -quiet 2>&1 );
-        return 0 unless $cmd_echo =~ m{Firebird}ims;
+        App::Sqitch::X::hurl('isql not for Firebird')
+             unless $cmd_echo =~ m{Firebird}ims;
         chomp $cmd_echo;
         say "# Detected $cmd_echo";
         # Skip if no DBD::Firebird.
-        return 0 unless $have_fb_driver;
+        App::Sqitch::X::hurl('DBD::Firebird did not load')
+            unless $have_fb_driver;
         say "# Connected to Firebird $fb_version" if $fb_version;
         return 1;
     },

t/lib/DBIEngineTest.pm

@@ -88,7 +88,7 @@ sub run {
         );
         if (my $code = $p{skip_unless}) {
             try {
-                $code->( $engine ) || die 'NO';
+                $code->( $engine ) || App::Sqitch::X::hurl('NO');
             } catch {
                 plan skip_all => sprintf(
                     'Unable to live-test %s engine: %s',