community/mumudvb: Add proper dependencies

mumudvb currently depends on gettext, but it is not listed in the
depencies variable, causing the following errror:

 configure.ac:27: warning: macro 'AM_ICONV' not found in library
 configure.ac:27: error: possibly undefined macro: AM_ICONV
       If this token and others are legitimate, please use m4_pattern_allow.
       See the Autoconf documentation.
 autoreconf: /usr/bin/autoconf failed with exit status: 1

Adding the proper depedency fix this issue and the package builds fine