ci: preserve PATH when running waf under sudo

Change-Id: Id178dba19d34b8f5f76de34cfe8407078e2f3409
Refs: #4186
diff --git a/.jenkins.d/10-build.sh b/.jenkins.d/10-build.sh
index 6dd2326..6c4928d 100755
--- a/.jenkins.d/10-build.sh
+++ b/.jenkins.d/10-build.sh
@@ -12,7 +12,7 @@
 sudo rm -f /usr/local/lib/pkgconfig/libndn-cxx.pc
 
 # Cleanup
-sudo ./waf -j1 --color=yes distclean
+sudo env "PATH=$PATH" ./waf -j1 --color=yes distclean
 
 if [[ $JOB_NAME != *"code-coverage" && $JOB_NAME != *"limited-build" ]]; then
   # Configure/build static library in optimized mode with tests
@@ -20,14 +20,14 @@
   ./waf -j1 --color=yes build
 
   # Cleanup
-  sudo ./waf -j1 --color=yes distclean
+  sudo env "PATH=$PATH" ./waf -j1 --color=yes distclean
 
   # Configure/build static and shared library in optimized mode without tests
   ./waf -j1 --color=yes configure --enable-static --enable-shared
   ./waf -j1 --color=yes build
 
   # Cleanup
-  sudo ./waf -j1 --color=yes distclean
+  sudo env "PATH=$PATH" ./waf -j1 --color=yes distclean
 fi
 
 # Configure/build shared library in debug mode with tests/examples and without precompiled headers
@@ -42,7 +42,7 @@
 # (tests will be run against debug version)
 
 # Install
-sudo ./waf -j1 --color=yes install
+sudo env "PATH=$PATH" ./waf -j1 --color=yes install
 
 if has Linux $NODE_LABELS; then
     sudo ldconfig
diff --git a/.travis.yml b/.travis.yml
index d5ff924..8be7822 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -135,6 +135,7 @@
 
 before_script:
   - ${CXX:-c++} --version
+  - python --version
 
 script:
   - ./.jenkins