Install python3 on Fedora29

GDB doesn't accept older 2.x as a valid choice.

Signed-off-by: Alexey Neyman <stilor@att.net>

testing/docker/fedora29/Dockerfile

@@ -4,7 +4,7 @@ ARG CTNG_GID
 RUN groupadd -g $CTNG_GID ctng
 RUN useradd -d /home/ctng -m -g $CTNG_GID -u $CTNG_UID -s /bin/bash ctng
 RUN yum install -y autoconf gperf bison file flex texinfo help2man gcc-c++ libtool make patch \
-    ncurses-devel python-devel perl-Thread-Queue bzip2 git wget which xz unzip
+    ncurses-devel python3-devel perl-Thread-Queue bzip2 git wget which xz unzip
 RUN wget -O /sbin/dumb-init https://github.com/Yelp/dumb-init/releases/download/v1.2.1/dumb-init_1.2.1_amd64
 RUN chmod a+x /sbin/dumb-init
 RUN echo 'export PATH=/opt/ctng/bin:$PATH' >> /etc/profile