Incorrect supported Ruby version in doc/INSTALL (#30161).

Patch by Go MAEDA.

git-svn-id: http://svn.redmine.org/redmine/trunk@17815 e93f8b46-1217-0410-a6f0-8f06a7374b81

doc/INSTALL

@@ -7,7 +7,7 @@ http://www.redmine.org/
 
 == Requirements
 
-* Ruby >= 2.2.1
+* Ruby >= 2.2.2
 * RubyGems
 * Bundler >= 1.5.0
 
@@ -29,7 +29,7 @@ Optional:
 2. Create an empty utf8 encoded database: "redmine" for example
 
 3. Configure the database parameters in config/database.yml
-   for the "production" environment (default database is MySQL and ruby1.9)
+   for the "production" environment (default database is MySQL)
 
 4. Install the required gems by running:
      bundle install --without development test