azure: docker: pipe downloaded archives into tar(1) directly

When building dependencies for our Docker images, we first download the
sources to disk first, unpack them and finally remove the archive again.
This can be sped up by piping the downloading archive into tar(1)
directly to parallelize both tasks. Furthermore, let's silence curl(1)
to not print to status information to stderr, which tends to be
interpreted as errors by Azure Pipelines.

azure-pipelines/docker/bionic

@@ -25,9 +25,8 @@ RUN apt-get update && \
 RUN mkdir /var/run/sshd
 
 RUN cd /tmp && \
-    curl -LO https://tls.mbed.org/download/mbedtls-2.16.2-apache.tgz && \
-    tar -xf mbedtls-2.16.2-apache.tgz && \
-    rm -f mbedtls-2.16.2-apache.tgz && \
+    curl --location --silent https://tls.mbed.org/download/mbedtls-2.16.2-apache.tgz | \
+    tar -xz && \
     cd mbedtls-2.16.2 && \
     scripts/config.pl set MBEDTLS_MD4_C 1 && \
     CFLAGS=-fPIC cmake -G Ninja -DENABLE_PROGRAMS=OFF -DENABLE_TESTING=OFF -DUSE_SHARED_MBEDTLS_LIBRARY=OFF -DUSE_STATIC_MBEDTLS_LIBRARY=ON . && \

azure-pipelines/docker/xenial

@@ -27,9 +27,8 @@ RUN apt-get update && \
 
 FROM apt AS mbedtls
 RUN cd /tmp && \
-    curl -LO https://tls.mbed.org/download/mbedtls-2.16.2-apache.tgz && \
-    tar -xf mbedtls-2.16.2-apache.tgz && \
-    rm -f mbedtls-2.16.2-apache.tgz && \
+    curl --location --silent https://tls.mbed.org/download/mbedtls-2.16.2-apache.tgz | \
+    tar -xz && \
     cd mbedtls-2.16.2 && \
     scripts/config.pl set MBEDTLS_MD4_C 1 && \
     CFLAGS=-fPIC cmake -G Ninja -DENABLE_PROGRAMS=OFF -DENABLE_TESTING=OFF -DUSE_SHARED_MBEDTLS_LIBRARY=OFF -DUSE_STATIC_MBEDTLS_LIBRARY=ON . && \
@@ -39,9 +38,8 @@ RUN cd /tmp && \
 
 FROM mbedtls AS libssh2
 RUN cd /tmp && \
-    curl -LO https://www.libssh2.org/download/libssh2-1.8.2.tar.gz && \
-    tar -xf libssh2-1.8.2.tar.gz && \
-    rm -f libssh2-1.8.2.tar.gz && \
+    curl --location --silent https://www.libssh2.org/download/libssh2-1.8.2.tar.gz | \
+    tar -xz && \
     cd libssh2-1.8.2 && \
     CFLAGS=-fPIC cmake -G Ninja -DBUILD_SHARED_LIBS=ON -DCRYPTO_BACKEND=Libgcrypt . && \
     ninja install && \
@@ -50,9 +48,8 @@ RUN cd /tmp && \
 
 FROM libssh2 AS valgrind
 RUN cd /tmp && \
-    curl -LO https://sourceware.org/pub/valgrind/valgrind-3.15.0.tar.bz2 && \
-    tar -xf valgrind-3.15.0.tar.bz2 && \
-    rm -f valgrind-3.15.0.tar.bz2 && \
+    curl --location --silent https://sourceware.org/pub/valgrind/valgrind-3.15.0.tar.bz2 | \
+    tar -xj && \
     cd valgrind-3.15.0 && \
     ./configure && \
     make && \