[travis] Exit early when check-doc.py fails

.travis.yml

@@ -58,6 +58,7 @@ install:
     - if [ -n "$PACKAGES" ]; then travis_retry sudo apt-get install --no-install-recommends --no-upgrade -qq $PACKAGES; fi
 before_script:
     - unset CC; unset CXX
+    - if [ "$CHECK_DOC" = 1 ]; then contrib/devtools/check-doc.py; fi
     - mkdir -p depends/SDKs depends/sdk-sources
     - if [ -n "$OSX_SDK" -a ! -f depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz ]; then curl --location --fail $SDK_URL/MacOSX${OSX_SDK}.sdk.tar.gz -o depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz; fi
     - if [ -n "$OSX_SDK" -a -f depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz ]; then tar -C depends/SDKs -xf depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz; fi
@@ -68,7 +69,6 @@ script:
     - BITCOIN_CONFIG_ALL="--disable-dependency-tracking --prefix=$TRAVIS_BUILD_DIR/depends/$HOST --bindir=$OUTDIR/bin --libdir=$OUTDIR/lib"
     - depends/$HOST/native/bin/ccache --max-size=$CCACHE_SIZE
     - if [ "$TRAVIS_PULL_REQUEST" != "false" ]; then export CCACHE_READONLY=1; fi
-    - if [ "$CHECK_DOC" = 1 ]; then contrib/devtools/check-doc.py; fi
     - test -n "$USE_SHELL" && eval '"$USE_SHELL" -c "./autogen.sh"' || ./autogen.sh
     - ./configure --cache-file=config.cache $BITCOIN_CONFIG_ALL $BITCOIN_CONFIG || ( cat config.log && false)
     - make distdir PACKAGE=bitcoin VERSION=$HOST