SSH BaseCommand: handle Throwable instead of Exception

If an admin accidentally deploys an incompatible plugin version, which
uses a non-existing or incompatible Gerrit core API, the runtime will
throw an Error which is not an Exception. For such cases we got nothing
logged as we didn't catch Throwables which are not Exception subtypes.

Release-Notes: skip
Change-Id: I64f674ab51ac237452009ee25c63977e0ff26040
diff --git a/java/com/google/gerrit/sshd/BaseCommand.java b/java/com/google/gerrit/sshd/BaseCommand.java
index f1be04e..2c373c5 100644
--- a/java/com/google/gerrit/sshd/BaseCommand.java
+++ b/java/com/google/gerrit/sshd/BaseCommand.java
@@ -501,7 +501,7 @@
 
           out.flush();
           err.flush();
-        } catch (Exception e) {
+        } catch (Throwable e) {
           try {
             out.flush();
           } catch (Exception e2) {