Merge #12839: test: Remove travis checkout depth

9df1a9c test: Remove travis checkout depth (Wladimir J. van der Laan)

Pull request description:

  Travis tests on branches of non-head commits are failing, because the depth of 1 doesn't allow checking them out.

  E.g.: https://travis-ci.org/bitcoin/bitcoin/jobs/360227253

  Remove `depth` as was the case before fa44af5, so that Travis can determine the minimum depth to check out.

Tree-SHA512: f193939cbef2aadd8d88fe522bd5ea84a3b72899f043279e3e8b546a70875a85561adf53e3f70c288833382eb71576c8fb6ef4db0588894c609fb58f5afce6df

Author: laanwj

.travis.yml

@@ -8,8 +8,6 @@ cache:
   - depends/built
   - depends/sdk-sources
   - $HOME/.ccache
-git:
-  depth: 1
 env:
   global:
     - MAKEJOBS=-j3