PatchSet: Correct misspelling and type of pushCertificate field

I519240547 extended the patch_sets table with a pushCertificate column
to store push the certificate that was used when pushing a signed
commit.

However, the column type VARCHAR(255) is too small for PGP certificate
descriptions. The column name was also misspelled as "pushCertficate"
(missing a 'i').

Extend the column from VARCHAR(255) to CLOB, as used in the account
table ssh key column. At the same time, correct the misspelling.

Reported-By: Henrik Laban Sköllermark <laban@kryo.se>
Change-Id: I3dff91041c00f619f06c0e64c5cb09e3987eac9a

gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/PatchSet.java

@@ -187,9 +187,11 @@ public final class PatchSet {
   @Column(id = 6, notNull = false)
   protected String groups;
 
+  //DELETED id = 7 (pushCertficate)
+
   /** Certificate sent with a push that created this patch set. */
-  @Column(id = 7, notNull = false)
-  protected String pushCertficate;
+  @Column(id = 8, notNull = false, length = Integer.MAX_VALUE)
+  protected String pushCertificate;
 
   protected PatchSet() {
   }
@@ -251,11 +253,11 @@ public final class PatchSet {
   }
 
   public String getPushCertificate() {
-    return pushCertficate;
+    return pushCertificate;
   }
 
   public void setPushCertificate(String cert) {
-    pushCertficate = cert;
+    pushCertificate = cert;
   }
 
   @Override