- sanitize BuildRequires with respect to packaging guidelines

In particular:

* glibc-devel is not the way to declare that build time environment
  (toolchain) for C code is required -- in fact that gcc was present
  in the buildroot was an accidental side-effect of libtool requiring
  "gcc(major)" at particular version:
  https://fedoraproject.org/wiki/Packaging:C_and_C%2B%2B#BuildRequires_and_Requires

* python3-devel package was not in BuildRequires despite the guidelines
  orders to do so:
  https://fedoraproject.org/wiki/Packaging:Python#Dependencies

* collapse overly long BuildRequire line regarding Python packages
  into multiple ones

Signed-off-by: Jan Pokorný <jpokorny@redhat.com>

fence-agents.spec

@@ -82,11 +82,19 @@ EOF)
 %endif
 
 # Build dependencies
-BuildRequires: glibc-devel
-BuildRequires: gnutls-utils
-BuildRequires: libxslt
-BuildRequires: python3-pexpect python3-pycurl python3-suds python3-requests openwsman-python3 python3-boto3 python3-google-api-client
+## general
 BuildRequires: autoconf automake libtool
+## compiled code (-kdump)
+BuildRequires: gcc
+## man pages generating
+BuildRequires: libxslt
+## establishing proper paths to particular programs
+BuildRequires: gnutls-utils
+## Python dependencies
+BuildRequires: python3-devel
+BuildRequires: python3-pexpect python3-pycurl python3-requests
+BuildRequires: python3-suds openwsman-python3 python3-boto3
+BuildRequires: python3-google-api-client
 
 %prep
 %setup -q -n %{name}-%{version}
@@ -932,6 +940,7 @@ The fence-agents-zvm package contains a fence agent for IBM z/VM over IP.
 #- mark non-compiled packages properly as noarch, restructure excludes
 #- move azure_fence.py and XenAPI.py to respective subpackages from -common
 #- sanitize allfenceagents internally defined enumeration
+#- sanitize BuildRequires with respect to packaging guidelines
 
 * Fri Jul 13 2018 Fedora Release Engineering <releng@fedoraproject.org> - 4.2.1-3
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_29_Mass_Rebuild