Fixed MariaDB install steps in travis

.travis.yml

@@ -7,6 +7,14 @@ services:
   - mysql
 
 install:
+  - sudo service mysql stop
+  - sudo apt-get install python-software-properties
+  - sudo apt-key adv --recv-keys --keyserver hkp://keyserver.ubuntu.com:80 0xcbcb082a1bb943db
+  - sudo add-apt-repository 'deb http://ftp.osuosl.org/pub/mariadb/repo/5.5/ubuntu precise main'
+  - sudo apt-get update
+  - sudo apt-get purge -y mysql-common
+  - sudo apt-get install mariadb-server mariadb-common libmariadbclient-dev
+	
   - CFLAGS=-O0 pip install git+https://github.com/frappe/frappe.git@develop &&
   - pip install --editable .