Cleanup .travis.sh and fix TravisCI (#90)

Summary:
* /bin/sh is not guaranteed to include `$()`, /bin/bash is
* Remove `composer.lock` to align with other hhvm projects
* `composer upgrade` can't install packages if `composer.lock` is missing, use `composer install` instead
* `vendor/**/tests` cause problems when composer clones dependencies instead of using release tarballs.
Pull Request resolved: #90

Reviewed By: wittgenst

Differential Revision: D20630520

Pulled By: yns88

fbshipit-source-id: 52c4422c2127ebf10d98152dea48cda62517544f

.gitignore

@@ -1 +1,2 @@
 vendor/
+composer.lock

.hhconfig

@@ -2,3 +2,4 @@ assume_php = false
 safe_array = true
 safe_vector_array = true
 version = 3.0.0
+ignored_paths = [ "^vendor/.*/tests?/" ]

.travis.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 set -ex
 
 add-apt-repository ppa:git-core/ppa
@@ -23,7 +23,7 @@ hhvm --version
 curl https://getcomposer.org/installer | php -- /dev/stdin --install-dir=/usr/local/bin --filename=composer
 
 cd /var/source
-php /usr/local/bin/composer update
+php /usr/local/bin/composer install
 
 hh_server --check $(pwd)
 vendor/bin/hacktest tests/