RFR: JDK-8239019: testmake fails with FATAL: VCS_TYPE is empty

[Erik Joelsson]

Hello,

The fix to make idea.sh support both git and mercurial had the 
unfortunate side effect of bailing out completely if neither was found. 
This happens to be the case when we run our build system tests (which 
includes running idea.sh) in our distributed test environment. I think 
idea.sh should still work even if run on a source tree outside of any 
source control system.

This patch just changes the lack of a detected VCS_TYPE to a warning 
instead of being fatal. The vcs.xml is still generated, but from what I 
can tell, Intellij doesn't seem to care much.

Webrev: http://cr.openjdk.java.net/~erikj/8239019/webrev.01

Bug: https://bugs.openjdk.java.net/browse/JDK-8239019

/Erik