Use runkit7 while testing PHP 7 on Travis

Signed-off-by: Michal Čihař <michal@cihar.com>

test/install-runkit

@@ -1,4 +1,5 @@
 #!/bin/bash
+set -e
 
 # Do not run as CGI
 if [ -n "$GATEWAY_INTERFACE" ] ; then
@@ -8,14 +9,16 @@ fi
 
 # These do not support runkit
 case "$TRAVIS_PHP_VERSION" in
-    hhvm*|7.0|7.1|7.2|nightly)
+    hhvm*|nightly)
         exit 0
         ;;
+    7.*)
+        wget https://github.com/runkit7/runkit7/releases/download/1.0.5b1/runkit-1.0.5b1.tgz
+        pecl install ./runkit-1.0.5b1.tgz
+        ;;
+    *)
+        pecl install runkit
+        ;;
 esac
 
-set -e
-set -x
-
-pecl install runkit
-
 phpenv config-add test/php-runkit.ini