Remove nonsense default value on NOT NULL TIMESTAMP

MySQL doesn't like our phony default value when the local timezone
is GMT+10, apparently that's still a date that is out of range for
the MySQL server.

Instead of registering a phony default which is never used, we
should just leave the default out and require that anyone who does
an INSERT will populate the column.  Certainly any insert done from
the ORM's own code will always populate the column.

Signed-off-by: Shawn O. Pearce <sop@google.com>
diff --git a/src/main/java/com/google/gwtorm/schema/sql/DialectMySQL.java b/src/main/java/com/google/gwtorm/schema/sql/DialectMySQL.java
index d9d2ce2..6b96faf 100644
--- a/src/main/java/com/google/gwtorm/schema/sql/DialectMySQL.java
+++ b/src/main/java/com/google/gwtorm/schema/sql/DialectMySQL.java
@@ -57,12 +57,6 @@
         return r.toString();
       }
     });
-    types.put(java.sql.Timestamp.class, new SqlTimestampTypeInfo() {
-      @Override
-      public String getSqlDefault() {
-        return "'1970-01-01 00:00:01'";
-      }
-    });
   }
 
   @Override
diff --git a/src/main/java/com/google/gwtorm/schema/sql/SqlTimestampTypeInfo.java b/src/main/java/com/google/gwtorm/schema/sql/SqlTimestampTypeInfo.java
index 79be0b9..ef60d29 100644
--- a/src/main/java/com/google/gwtorm/schema/sql/SqlTimestampTypeInfo.java
+++ b/src/main/java/com/google/gwtorm/schema/sql/SqlTimestampTypeInfo.java
@@ -34,14 +34,8 @@
     final StringBuilder r = new StringBuilder();
     r.append(dialect.getSqlTypeName(getSqlTypeConstant()));
     if (col.isNotNull()) {
-      r.append(" DEFAULT ");
-      r.append(getSqlDefault());
       r.append(" NOT NULL");
     }
     return r.toString();
   }
-
-  public String getSqlDefault() {
-    return "'1900-01-01 00:00:00'";
-  }
 }