Make version compare to work with all deployment branches etc.

the following works with various test cases:

if ( !version_compare( '1.22alpha', '1.22c', '<' ) ) {
  die( 1 );
}

$this->assertTrue( version_compare( '1.21wmf21', '1.22c', '<' ), '1.21wmf21 is incompatible' );
$this->assertTrue( version_compare( '1.21.2', '1.22c', '<' ), '1.21.2 is incompatible' );
$this->assertFalse( version_compare( '1.22wmf21', '1.22c', '<' ), '1.22wmf21 is compatible' );
$this->assertFalse( version_compare( '1.22alpha', '1.22c', '<' ), '1.22alpha is compatible' );

seems version_compare works in strange ways...

Change-Id: I23e3e052defe42c9ab2ee3be94e07766242853a8
Merge "Make version compare to work with all deployment branches etc."