Rename plugins SDK "project.dir" to "sdk.dir"

• Type: Story
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 6.2.0 CE M6
• Fix Version/s: 6.1.30 EE GA3, 6.2.0 CE M6
• Component/s: Dev Tools, Dev Tools > Plugins SDK
• Labels: None
• Branch Version/s:
  6.1.x
• Backported to Branch:
  Committed
• Epic/Theme:
  • Quick_Win
• Business Value: 3
• Git Pull Request: https://github.com/brianchandotcom/liferay-plugins/pull/1524

We are going to rename "project.dir" to "sdk.dir". This makes it more obvious what the variable refers to as project.dir could be interpreted as a plugins/liferay/sdk/etc base directory.

sdk.dir = The root directory of the plugins sdk (which is determined by where build-common.xml is)