diff --git a/.travis.yml b/.travis.yml
index 08a34e673a..879909033f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -38,6 +38,7 @@ env:
 
 before_install:
     - export PATH=$(echo $PATH | tr ':' "\n" | sed '/\/opt\/python/d' | tr "\n" ":" | sed "s|::|:|g")
+    - export PATH=$(echo $PATH | tr ':' "\n" | sed '/\/opt\/pyenv/d' | tr "\n" ":" | sed "s|::|:|g")
 install:
     - if [ -n "$PPA" ]; then travis_retry sudo add-apt-repository "$PPA" -y; fi
     - if [ -n "$DPKG_ADD_ARCH" ]; then sudo dpkg --add-architecture "$DPKG_ADD_ARCH" ; fi
diff --git a/src/validation.cpp b/src/validation.cpp
index 5a3e98c829..a54a4d9820 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -3888,7 +3888,9 @@ bool ContextualCheckBlock(const CBlock& block, CValidationState& state, const Co
         int commitpos = GetWitnessCommitmentIndex(block);
         if (commitpos != -1) {
             uint256 hashWitness = BlockWitnessMerkleRoot(block);
-            if ((block.vtx[0]->wit.vtxinwit.size() > 0 &&block.vtx[0]->wit.vtxinwit[0].scriptWitness.stack.size() != 1) || block.vtx[0]->wit.vtxinwit[0].scriptWitness.stack[0].size() != 32) {
+            if (block.vtx[0]->wit.vtxinwit.empty()
+                || block.vtx[0]->wit.vtxinwit[0].scriptWitness.stack.size() != 1
+                || block.vtx[0]->wit.vtxinwit[0].scriptWitness.stack[0].size() != 32) {
                 return state.DoS(100, false, REJECT_INVALID, "bad-witness-nonce-size", true, strprintf("%s : invalid witness nonce size", __func__));
             }
             CHash256().Write(hashWitness.begin(), 32).Write(&block.vtx[0]->wit.vtxinwit[0].scriptWitness.stack[0][0], 32).Finalize(hashWitness.begin());