travis: add uthash-devel

Reuse uthash library for the test code.

Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
diff --git a/.travis.yml b/.travis.yml
index 1692ac9..7c5a67e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -29,6 +29,7 @@
     - realpath
     - lcov
     - libssl-dev
+    - uthash-dev
   coverity_scan:
     project:
       name: "01org/TPM2.0-TSS"