Revert "Make valgrind run on travis tests of v8js"

This reverts commit 3e862b1aa1fba50bafad83844862e9657bb2f8c0.

Valgrind reports memory leaks with all test on PHP with ZTS,
which it doesn't do locally.  More investigation needed ...

.travis.yml

@@ -8,11 +8,7 @@ php:
 env:
   - V8VER=5.2
   - V8VER=5.1
-  - V8VER=5.2 VALGRIND=1
 
 before_install: make -f Makefile.travis before_install
-install:
-  - if [ "$VALGRIND" = 1 ]; then sudo apt-get install -qq valgrind; export TEST_PHP_ARGS="-m"; fi
-  - make -f Makefile.travis install
-
+install: make -f Makefile.travis install
 script: make -f Makefile.travis test