ci: Attempt to stabilize builds on Travis-CI

Change-Id: Ie13b4509504ffdc442200a38ac6437ed44c5b73a
diff --git a/.jenkins.d/10-get-ndk.sh b/.jenkins.d/10-get-ndk.sh
index 79368f0..5729869 100755
--- a/.jenkins.d/10-get-ndk.sh
+++ b/.jenkins.d/10-get-ndk.sh
@@ -2,18 +2,23 @@
 set -e
 set -x
 
-if [ ! -f downloads/crystax-ndk-10.1.0-linux-x86_64.7z ]; then
+URL=https://www.crystax.net/download/
+NDK=crystax-ndk-10.1.0
+
+NDK_FILE="$NDK-linux-x86_64.tar.bz2"
+
+if [ ! -f downloads/$NDK_FILE ]; then
     mkdir downloads || true
     cd downloads
-    wget --no-check-certificate https://www.crystax.net/download/crystax-ndk-10.1.0-linux-x86_64.7z
+    wget --no-check-certificate $URL$NDK_FILE
     cd ..
 fi
 
-if [ ! -d crystax-ndk-10.1.0 ]; then
-  echo -en 'travis_fold:start:NDK\r'
-  7z x downloads/crystax-ndk-10.1.0-linux-x86_64.7z > /dev/null
-  find crystax-ndk-10.1.0 -name byteswap.h -exec sed -i -e 's/ swap/ bswap/g' {} \;
-  echo -en 'travis_fold:end:NDK\r'
+if [ ! -d $NDK ]; then
+    echo -en 'travis_fold:start:NDK\r'
+    pv -f downloads/$NDK_FILE | tar xjf -
+    find $NDK -name byteswap.h -exec sed -i -e 's/ swap/ bswap/g' {} \;
+    echo -en 'travis_fold:end:NDK\r'
 fi
 
-echo ndk.dir=`pwd`/crystax-ndk-10.1.0 >> local.properties
+echo ndk.dir=`pwd`/$NDK >> local.properties
diff --git a/.travis.yml b/.travis.yml
index 315e0b8..3f44238 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -27,7 +27,7 @@
  - NDK_BUILD_ABI=x86
  - NDK_BUILD_ABI=x86_64
 before_install:
-  - travis_retry sudo apt-get install -y build-essential unzip wget p7zip-full
+  - travis_retry sudo apt-get install -y build-essential unzip wget pv
   - travis_retry .jenkins.d/10-get-ndk.sh
 script:
   - GRADLE_OPTS="-Xmx768m -Xms256m -Xss1m" NDK_BUILD_PARALLEL=1 gradle assembleRelease