build: Disable installation of unit tests on `./waf install`

Fixes #1547

Change-Id: Iee30f82b662a606f95ae0bfc9d2adac53c8aed4a
diff --git a/tests/other/wscript b/tests/other/wscript
index 20cae46..69aa2bb 100644
--- a/tests/other/wscript
+++ b/tests/other/wscript
@@ -29,4 +29,5 @@
     bld.program(target="../../cs-smoketest",
                 source="cs-smoketest.cpp",
                 use='daemon-objects',
-                install_path=None)
+                install_path=None,
+                )
diff --git a/tests/wscript b/tests/wscript
index bf56913..8b9c6fc 100644
--- a/tests/wscript
+++ b/tests/wscript
@@ -43,7 +43,7 @@
             source=bld.path.ant_glob(['core/**/*.cpp']),
             use='core-objects unit-tests-main',
             includes='.',
-            install_prefix=None,
+            install_path=None,
           )
 
         # NFD tests
@@ -55,7 +55,7 @@
                                            'daemon/face/unix-*.cpp']),
             use='daemon-objects unit-tests-main',
             includes='.',
-            install_prefix=None,
+            install_path=None,
           )
 
         if bld.env['HAVE_LIBPCAP']:
@@ -70,7 +70,7 @@
             source=bld.path.ant_glob(['rib/**/*.cpp']),
             use='rib-objects unit-tests-main',
             includes=['.'],
-            install_prefix=None,
+            install_path=None,
           )
 
     # Other tests (e.g., stress tests that can be enabled even if unit tests are disabled)