Fix /usr/local/lib/crew/lib/buildsystems/pip.rb:21:in eval: no implicit conversion of nil into String (TypeError) (#8877)

lib/buildsystems/pip.rb

@@ -18,6 +18,6 @@ class Pip < Package
       @destpath = "#{CREW_DEST_DIR.chomp('/')}#{@pip_path}"
       FileUtils.install @pip_path, @destpath
     end
-    eval @pip_install_extras
+    eval @pip_install_extras if @pip_install_extras
   end
 end

lib/const.rb

@@ -1,6 +1,6 @@
 # lib/const.rb
 # Defines common constants used in different parts of crew
-CREW_VERSION = '1.38.2'
+CREW_VERSION = '1.38.3'
 
 # kernel architecture
 KERN_ARCH = `uname -m`.chomp